JP2017012580A - Fundus imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To acquire a useful fundus image during a diagnosis of a fundus, using a simplified structure.SOLUTION: An imaging apparatus 1 comprises: a plurality of apertures As for scattered light spaced apart from one another relative to a first direction (X direction) on a fundus conjugate plane of a first imaging optical system 100b; and a control unit 800 for controlling the positions of the plurality of apertures As for scattered light in an integrated manner. The plurality of apertures As for scattered light include at least two apertures arranged in different positions relative to a direction (Y direction) orthogonal to the first direction. In the imaging apparatus 1, the apertures arranged on a light path (K1+K2) of the scattered light are switched between the two apertures, and also the arrangement of the two apertures on the light path of the scattered light is switched to two different positions relative to the first direction, so that the direction of the scattered light guided to a light receiving element 56 is switched to four directions different from one another.SELECTED DRAWING: Figure 3

Description

  The present disclosure relates to a fundus photographing apparatus for photographing the fundus of a subject's eye and performing fundus observation.

  2. Description of the Related Art Conventionally, a fundus photographing apparatus that obtains a fundus image by scanning laser light two-dimensionally over the fundus and receiving the reflected light is known. In such a fundus imaging apparatus, for example, a ring aperture made up of a ring-shaped opening and a black spot plate is arranged at a position conjugate with the fundus of the eye to be examined, so that reflected light from the condensing position (focal position) at the observation site can be obtained. There is a known technique (scattered light imaging) of limiting and receiving scattered light from before and after that and imaging it (see Patent Document 1).

  Patent Document 1 describes a method of switching the direction of scattered light guided to a light receiving element by changing the passage region of scattered light.

JP 2009-95632 A

  However, if the direction of scattered light guided to the light receiving element is to be more diversified, for example, the apparatus configuration is likely to be complicated.

  The present disclosure has been made in view of the problems of the prior art, and an object of the present disclosure is to provide a fundus imaging apparatus that can obtain a fundus image useful in fundus diagnosis with a simple configuration.

  A fundus imaging apparatus according to a first aspect of the present disclosure includes an optical member for condensing laser light on an observation surface of the fundus, and a scanning unit that two-dimensionally scans the fundus with the laser light. An irradiation optical system, a photographing optical system that obtains a photographed image by receiving reflected light of the laser beam reflected by the fundus, and a fundus conjugate plane of the photographing optical system that is orthogonal to the photographing optical axis. A plurality of apertures spaced apart from each other with respect to the first direction, and control means for integrally controlling the positions of the plurality of apertures, the plurality of apertures including the first aperture and the first aperture At least a second aperture arranged at a position different from the first aperture with respect to a direction orthogonal to one direction, and the control means moves the plurality of apertures in the first direction. The aperture arranged on the optical path of the scattered light scattered before and after the condensing point of the observation surface is switched between the first aperture and the second aperture, and the aperture on the optical path of the scattered light is further changed. By switching the arrangement of the first aperture and the second aperture to two different positions with respect to the first direction, the direction of the scattered light guided to the light receiving element is switched to four different directions.

  According to the fundus imaging apparatus of the present disclosure, a fundus image useful in fundus diagnosis can be obtained with a simple configuration.

It is the schematic diagram which showed the optical system of the imaging device of this embodiment. It is a figure at the time of seeing the fundus conjugate surface where a plurality of apertures are provided from the eye side to be examined (the lens 53 side in FIG. 1). It is a figure at the time of seeing a light-shielding unit from the to-be-tested eye side (the lens 53 side of FIG. 1) rather than it. It is the figure which showed the position where each aperture is placed in this embodiment with the dotted line with respect to the fundus conjugate plane shown in FIG. FIG. 5 is a diagram showing, for each shift direction, components of scattered light passing through the aperture on the optical path (scattering direction with respect to the condensing point of the fundus) when the scattered light aperture is shifted in each direction intersecting the optical axis L2. Each figure is a figure seen from the optical axis direction. It is the block diagram which showed the control system of the imaging device of this embodiment. It is the figure which showed an example of the aperture setting controller. (A) is a first fundus image obtained by arranging an irregular light aperture at a position of 0 °, and (b) is a first fundus image obtained by arranging an irregular light aperture at a position of 180 °. Image (c) is a diagram schematically showing a composite image of the image (a) and the image (b).

  Hereinafter, exemplary embodiments of the present disclosure will be described with reference to the drawings. The imaging apparatus 1 according to the present embodiment scans the fundus two-dimensionally with laser light and receives the reflected light to obtain a fundus image (more specifically, a scanning laser ophthalmoscope). ). In particular, in the present embodiment, an apparatus (AO-SLO) with wavefront aberration compensation that captures a fundus image of the eye E with the wavefront aberration of the eye E corrected is illustrated as an imaging apparatus 1 and the description thereof will be given. Do.

<Overview of optical system>
First, the optical system of the photographing apparatus 1 will be described with reference to FIG. The imaging apparatus 1 of the present embodiment includes a fundus imaging optical system 100, a wavefront aberration detection optical system (hereinafter referred to as an aberration detection optical system) 110, aberration compensation units 20, 30, and 72, and a second imaging unit. 200 and an anterior ocular segment observation unit 700.

<Fundus imaging optical system>
The fundus imaging optical system 100 projects laser light (illumination light) on the eye E and receives reflected light from the fundus of the laser light to capture a fundus image of the eye E. The fundus of the eye E is photographed by the fundus imaging optical system 100 with high resolution (high resolution) and high magnification. As described below, the fundus imaging optical system 100 may have a configuration of a scanning laser ophthalmoscope using a confocal optical system, for example. The fundus imaging optical system 100 includes a first illumination optical system 100a (irradiation optical system) and a first imaging optical system 100b. In the present embodiment, the aberration compensation units 20, 30, and 72 are arranged in the fundus imaging optical system 100 in order to correct the aberration of the eye E.

  The first illumination optical system 100a has an optical member for condensing laser light on the observation surface of the fundus. Such an optical member may be, for example, a lens system, a mirror system, or a combination of both. In addition, it has scanning means (optical scanner) for two-dimensionally scanning the fundus with the laser beam. The first illumination optical system 100a illuminates the fundus two-dimensionally by irradiating the eye E with laser light and scanning the laser light on the fundus.

  The first illumination optical system 100a includes a light source 11, a lens 12, a polarization beam splitter (PBS) 14, a beam splitter (BS) 71, a concave mirror 16, in an optical path from the light source 11 (first light source) to the fundus. Concave mirror 17, flat mirror 18, aberration compensation unit 72 (wavefront compensation device 72), beam splitter (BS) 75, concave mirror 21, concave mirror 22, scanning unit 25, concave mirror 26, concave mirror 27, flat mirror 28, Aberration compensation unit 30 (astigmatism correction unit 30), lens 32, plane mirror 33, aberration compensation unit 20 (diopter correction unit 20), plane mirror 35, concave mirror 36, deflection unit 400, dichroic mirror 90, concave mirror 41, It has a plane mirror 42, a plane mirror 43, and a concave mirror 45.

  The light source 11 emits laser light. In the present embodiment, the laser light may emit a near-infrared wavelength that is difficult to be visually recognized by the eye E. The light source 11 may be any light source that emits spot light having a highly convergent characteristic. For example, the light source 11 may be an SLD or a semiconductor laser.

  The laser light emitted from the light source 11 is converted into parallel light by the lens 12 and then enters the wavefront compensation device 72 via the PBS 14, BS 71, concave mirrors 16 and 17, and the flat mirror 18. In the present embodiment, the laser light passes through the PBS 14 and becomes a light beam having only an S-polarized component. The wavefront compensation device 72 corrects higher-order aberrations of the eye E by controlling the wavefront of the incident light. The detailed configuration of the wavefront compensation device 72 will be described later. In the present embodiment, the laser beam is guided from the wavefront compensation device 72 to the BS 75, reflected by the concave mirror 21 and the concave mirror 22, and travels toward the scanning unit 25.

  In the present embodiment, the scanning unit 25 is used together with the deflecting unit 400 in order to scan laser light two-dimensionally on the fundus. The scanning unit 25 is a resonant mirror used for main scanning of laser light. The laser light is scanned in the X direction on the fundus by the scanning unit 25.

  The light that has passed through the scanning unit 25 enters the astigmatism correction unit 30 through the concave mirrors 26 and 27 and the plane mirror 28.

  The astigmatism correction unit 30 is a unit for correcting an astigmatism component (secondary) in the aberration of the eye E to be examined. As the astigmatism correction unit 30, various configurations such as a configuration including a cross cylinder lens are conceivable. The astigmatism correction unit 30 may correct the astigmatism component in the eye E according to a value indicating the astigmatism component measured for the eye E.

  The laser light that has passed through the astigmatism correction unit 30 is then incident on the diopter correction unit 20 via the lens 32 and the plane mirror 33.

  The diopter correction unit 20 is a unit for performing diopter correction. For example, the diopter correction unit 20 may be configured to correct the diopter (that is, the defocus component of the aberration of the eye E) by adjusting the optical path length of the optical system.

  The illumination light guided from the diopter correction unit 20 to the plane mirror 35 is reflected by the concave mirror 36 and travels toward the deflection unit 400.

  The deflecting unit 400 scans the laser light emitted from the light source 11 in the vertical direction (Y direction) on the fundus. Furthermore, the deflecting unit 400 is also used to move the scanning range of the laser light on the fundus. For example, in the present embodiment, the deflecting unit 400 may include two optical scanners (specifically, an X galvanometer mirror and a Y galvanometer mirror) having different directions of deflecting laser light.

  The light that has passed through the deflecting unit 400 is guided into the pupil of the eye E through the dichroic mirror 90, the concave mirror 41, the plane mirrors 42 and 43, and the concave mirror 45. At this time, the laser light is collected on the observation surface of the fundus. As described above, the laser beam is two-dimensionally scanned on the fundus by the operations of the scanning unit 25 and the deflecting unit 400.

  Further, the dichroic mirror 90 has a characteristic of transmitting a light beam from the second photographing unit 200 described later and reflecting a light beam from the light source 11 and a light source 76 described later. Note that the emission ends of the light sources 11 and 76 and the fundus of the eye E are conjugate. In this way, the first illumination optical system 100a is formed.

  Next, the first photographing optical system 100b will be described. The first imaging optical system 100 b receives the reflected light of the laser light irradiated on the fundus by the light receiving element 56. The imaging device 1 acquires a first fundus image (cell image, AO-SLO image) based on a signal from the light receiving element 56. The first imaging optical system 100b shares the optical path from the eye E to the BS 71 with the first illumination optical system 100a. Further, the first photographing optical system 100 includes elements arranged in the reflection side optical path of the BS 71, that is, a plane mirror 51, a PBS 52, a lens 53, a light shielding unit 54, a lens 55, and a light receiving element 56. In this embodiment, the light receiving element 56 is an APD (avalanche photodiode).

<Detailed configuration of shading unit>
In the present embodiment, the light shielding unit 54 shifts the position of the aperture two-dimensionally on the fundus conjugate plane K. This aperture is used to guide to the light receiving element 56 at least one of reflected light from the condensing point on the observation surface and scattered light scattered before and after the condensing point.

  The light shielding unit 54 in this embodiment includes a light shielding member 500 and a moving mechanism 510. The light blocking member 500 is placed on a plane (that is, a fundus conjugate plane K) that is orthogonal to the imaging optical axis L2 and includes a conjugate point with a condensing point of the observation plane on the fundus in the optical path of the first imaging optical system 100b. It is burned. In particular, in the present embodiment, the light shielding unit 54 is disposed at a position deviating from the common optical path with the first illumination optical system 100a in the optical path of the first imaging optical system 100b.

  The moving mechanism 510 displaces the light shielding member 500 in one direction (X direction in the example of FIG. 1) orthogonal to the photographing optical axis L2. In the present embodiment, the light shielding member 500 has a plurality of apertures that are spaced from each other with respect to the X direction (a first direction orthogonal to the photographing optical axis in the present embodiment). The plurality of apertures include at least a scattered light aperture As for scattered light imaging and a confocal aperture Ac for reflected light imaging. The light blocking member 500 of the present embodiment has a plurality of scattered light apertures As and one confocal aperture Ac (see FIG. 3).

  Here, an optical path of light passing through the fundus conjugate plane K will be described with reference to FIG. FIG. 2 is a diagram when the fundus conjugate surface K is viewed from the lens 53 side. In FIG. 2, the optical path of light passing through the fundus conjugate plane K is divided into a confocal optical path K1 and a scattered light optical path K2. The confocal optical path K1 is an optical path through which reflected light from a condensing point (condensing position) on the observation surface mainly passes, and is formed in a circular shape near the optical axis L2 of the first imaging optical system 100b. The scattered light path K2 is an optical path through which scattered light scattered mainly from before and after the condensing point passes, and is formed in a ring shape around the optical axis L2 of the first photographing optical system. When one of the scattered light aperture As and the confocal aperture Ac is placed at an intended position with respect to the optical path of light passing through the fundus conjugate plane K (that is, K1 + K2), the other aperture Are arranged outside the optical path, the interval between the apertures in the light shielding member 500 is set. That is, in the present embodiment, only the light passing through one aperture arranged on the fundus conjugate plane K is guided to the light receiving element 56, and the other light is blocked by the light blocking member 500.

  Although details will be described later, the confocal aperture Ac is disposed on the confocal optical path K1 by appropriately adjusting the position of the light shielding member 500 by the moving mechanism 510. In this case, the fundus reflection light of the laser light is reflected by the BS 71 and the flat mirror 51 when passing back the first illumination optical system 100a described above, and only the S-polarized light is transmitted by the PBS 52. The transmitted light is focused on the opening (pinhole) of the confocal aperture Ac via the lens 53. The reflected light focused at the aperture is received by the light receiving element 56 through the lens 55. Although a part of the illumination light is reflected on the cornea, most of the illumination light is removed by the confocal aperture Ac. As a result, the light receiving element 56 can receive reflected light from the fundus while suppressing the influence of corneal reflection. A light reception signal of the light receiving element 56 is processed by an image processing unit (for example, the control unit 800), and as a result, a first fundus image (also referred to as an AO-SLO image) is generated. Here, a bright-field image is obtained by the confocal aperture Ac arranged on the confocal optical path K1. For example, the first fundus image may be formed with an angle of view of about 1 ° to 5 °. In addition, by adjusting the focus, the confocal region of the condensing point on the fundus is set for any of various layers of the fundus such as a layer containing blood vessels, a layer containing micro capillaly, and a photoreceptor layer. The Then, an image of the layer in which the confocal region is set is obtained as the first fundus image.

  Here, the configuration of the light shielding unit 54 will be described in detail with reference to FIG. FIG. 3 shows the light shielding unit 54 when viewed from the lens 53 side. The moving mechanism 510 may be any mechanism that moves the light shielding member 500 in one direction, and various configurations are conceivable. FIG. 3 shows a case where a sliding screw mechanism is used as an example. In this case, the moving mechanism 510 includes, for example, a motor 511 (driving unit of the present embodiment), a screw shaft 512, and a connecting unit 513. The screw shaft 512 is connected to the rotation shaft of the motor 511. The connecting portion 513 is fixed to the light shielding member 500. In addition, the connecting portion 513 is formed with a female screw that is screwed with a male screw formed on the screw shaft 512. In such a moving mechanism 510, the light shielding member 500 is moved in the X direction together with the connecting portion 513 by rotating the screw shaft 512.

  As described above, the light shielding member 500 is provided with the scattered light aperture As and the confocal aperture Ac. The confocal aperture Ac is formed at the same position as the optical axis L2 in the Y direction (that is, the direction orthogonal to both the X direction as the moving direction of the light blocking member 500 and the optical axis L2). In the present embodiment, the confocal aperture Ac is formed in the light shielding member 500 as, for example, a circular opening having a diameter of about 100 μm.

  The plurality of scattered light apertures As are used to change the scattering direction of the scattered light received by the light receiving element 56 among the scattered light scattered from before and after the condensing point to various directions. . In the present embodiment, the light shielding member 500 is formed with five scattered light apertures As.

  Each of the scattered light apertures As is formed in the light shielding member 500, for example, as a circular opening having a diameter of about 500 μm. The diameter of this circular opening is a smaller value than the radius of the optical path K in this embodiment. By setting the scattered light aperture As to be a circular opening having such a diameter, the scattered light of a collective amount of light is received while suppressing variations in the scattering direction of each light beam included in the scattered light guided to the light receiving element 56. The element 56 can easily receive light. As a result, a good scattered light image can be easily obtained. However, the shape of the scattered light aperture As may be a geometric shape other than a circle (for example, a semicircular shape (also referred to as a knife edge shape), an ellipse, a polygon, etc.).

  Further, each of the scattered light apertures As is arranged with an interval in the X direction from other apertures. The scattered light apertures As are formed at different positions in the Y direction. Therefore, in the present embodiment, the plurality of scattered light apertures As include one or more apertures formed at positions away from the conjugation point of the condensing point in the Y direction.

  When the light shielding member 500 is moved in the X direction by driving the driving unit 511, one of the scattered light aperture As and the confocal aperture Ac is selected from the optical path of light passing through the fundus conjugate plane K (that is, K1 + K2) can be switched and arranged. Here, the moving mechanism 510 is provided with a sensor 520 (for example, a photo sensor, a magnetic sensor, or the like). The sensor 520 detects the position of the light shielding member 500. For example, the sensor 520 may output an output signal indicating the displacement of the light shielding member 500 from a predetermined origin position. When switching the arrangement of the aperture with respect to the optical path of the first imaging optical system 100b, for example, the control unit 800 responds to the difference between the displacement from the origin position to the target position and the current displacement indicated by the signal from the sensor 520. The drive unit 511 may be driven with a drive amount.

  In the present embodiment, the control unit 800 controls the drive unit 511 so that the position of the light shielding member 500 is switched to nine positions. For example, information regarding each position (for example, information indicating the displacement between each position and the origin position) may be stored in the storage unit 801 in advance. At this time, as described above, the drive control of the drive unit 511 may be performed based on the information regarding this position and the signal from the sensor 520. The symbols Pd, P0 °, P45 °, P90 °, P135 °, P180 °, P225 °, P270 °, and P315 ° shown in FIG. 3 indicate the passing position of the optical axis L2 on the light shielding member 500 at each position. . When the optical axis L2 is placed on Pd, the confocal aperture Ac is disposed on the confocal point with the condensing point on the observation surface.

  Further, when the optical axis L2 is placed at each of the positions P0 °, P45 °, P90 °, P135 °, P180 °, P225 °, P270 °, and P315 °, it is viewed from the lens 53 side (that is, the eye side to be examined). Any one of the scattered light apertures As has 0 °, 45 °, 90 °, 135 °, 180 °, 225 °, 270 °, and 315 ° around the optical axis L2 on the scattered light optical path K2. It arrange | positions in a position (refer FIG. 4). In this embodiment, at any position, the scattered light aperture As disposed on the scattered light optical path K2 is equidistant from the optical axis L2 (in other words, on the same circumference around the optical axis L2). The control unit 800 controls the driving unit 511 so as to be arranged. As a result of the drive control, regardless of the position of the scattered light aperture As on the scattered light path K2, the scattered light has the same shooting conditions except for the direction of the scattered light viewed from the shooting optical axis direction. The first fundus image can be obtained. When the scattered light aperture As is set on the scattered light optical path K <b> 2, an image (dark field image) in which the scattered portion of the scattered light guided to the light receiving element 56 is emphasized is obtained. In AO-SLO that images the fundus at the cellular level, such scattered light imaging is useful in, for example, observation and analysis of blood vessels (more specifically, blood vessel walls) and micro capillaly.

  Of the plurality of scattered light apertures As, the aperture As1 formed at the same position as the optical axis L2 with respect to the Y direction is switched to a position of 0 ° and a position of 180 ° with respect to the optical axis L2. Is done. The aperture As1 is disposed at a position of 0 ° when the optical axis L2 is disposed at P0 °, and guides scattered light passing through the right side of the optical axis L2 to the light receiving element 56. In this case, as shown in FIG. 5A, the scattered light scattered in the direction of 0 ° from the front and back of the condensing point on the fundus mainly passes through the aperture As1. In FIG. 5, the scattered light passing through the aperture on the scattered light optical path K2 is indicated by an arrow from the condensing point indicated by a solid line. Moreover, in FIG. 5, the scattered light shielded by the light shielding member is indicated by an arrow indicated by a dotted line. The aperture As1 is arranged at a position of 180 ° when the optical axis L2 is arranged at P180 °, and guides scattered light passing through the left side of the optical axis L2 to the light receiving element 56. In this case, as shown in FIG. 5B, the scattered light scattered in the direction of 180 ° from the front and back of the condensing point on the fundus mainly passes through the aperture As1.

  Of the plurality of scattered light apertures As, the aperture As2 formed at a position away from the optical axis L2 in the Y direction is switched between a 45 ° position and a 135 ° position with respect to the optical axis L2. Be placed. The aperture As2 is arranged at a position of 45 ° when the optical axis L2 is arranged at P45 °, and guides scattered light passing through the upper right side of the optical axis L2 to the light receiving element 56. In this case, as shown in FIG. 5 (c), the scattered light scattered in the direction of 45 ° from around the focal point on the fundus mainly passes through the aperture As2. The aperture As2 is arranged at a position of 135 ° when the optical axis L2 is arranged at P135 °, and guides scattered light passing through the upper left side of the optical axis L2 to the light receiving element 56. In this case, as shown in FIG. 5 (d), scattered light scattered in the direction of 45 ° from around the focal point on the fundus mainly passes through the aperture As2. As described above, when the light shielding member 54 is displaced in the X direction, the aperture As2 is switched between the 45 ° position and the 135 ° position with respect to the optical axis L2, thereby the light receiving element 56. The direction of the scattered light guided to is switched to the opposite direction with respect to the X direction.

  Among the plurality of scattered light apertures As, the aperture As3 is formed at a position further away from the optical axis L2 than the aperture As2 in the Y direction. The aperture As3 is arranged at a position of 90 ° when the optical axis L2 is arranged at P90 °, and guides the scattered light passing above the optical axis L2 to the light receiving element 56. In this case, as shown in FIG. 5 (e), scattered light scattered in the direction of 90 ° from around the focal point on the fundus mainly passes through the aperture As3.

  Of the plurality of scattered light apertures As, the aperture As4 formed at a position away from the optical axis L2 in the Y direction is switched to a position of 315 ° and a position of 225 ° with respect to the optical axis L2. Be placed. The aperture As4 is arranged at a position of 315 ° when the optical axis L2 is arranged at P315 °, and guides the scattered light passing through the lower right side of the optical axis L2 to the light receiving element 56. In this case, as shown in FIG. 5 (f), the scattered light scattered in the direction of 315 ° from around the focal point on the fundus mainly passes through the aperture As4. The aperture As4 is arranged at a position of 225 ° when the optical axis L2 is arranged at P225 °, and guides scattered light passing through the lower left side of the optical axis L2 to the light receiving element 56. In this case, as shown in FIG. 5 (g), the scattered light scattered in the direction of 315 ° from before and after the condensing point on the fundus mainly passes through the aperture As4. As described above, the aperture As4 is switched between the position of 315 ° and the position of 225 ° with respect to the optical axis L2, so that the direction of the scattered light guided to the light receiving element 56 is changed in the X direction. Switch in the opposite direction.

  Among the plurality of scattered light apertures As, the aperture As5 is formed at a position further away from the optical axis L2 than the aperture As4 in the Y direction. The aperture As5 is arranged at a position of 270 ° when the optical axis L2 is arranged at P270 °, and guides scattered light passing below the optical axis L2 to the light receiving element 56. In this case, as shown in FIG. 5 (h), the scattered light scattered in the direction of 270 ° from before and after the condensing point on the fundus mainly passes through the aperture As5.

  Thus, in this embodiment, two or more scattered light apertures As are formed at different positions with respect to the direction orthogonal to the moving direction (X direction) of the light shielding member 500. The light blocking member 500 is displaced in the X direction by the drive unit 511, and the aperture disposed on the scattered light region K2 in the scattered light aperture As is switched to another aperture, thereby being disposed on the scattered light region K2. The position of the scattered light aperture As is shifted with respect to the Y direction. As a result, the direction of the scattered light guided to the light receiving element 56 is changed with respect to the Y direction. In particular, with respect to the Y direction, the aperture arranged in the scattered light region K2 is switched between the apertures formed across the optical axis L2 (that is, between As2, As3 and As4, As5). Thus, the direction of the scattered light guided to the light receiving element 56 is switched to the opposite direction with respect to the Y direction.

    In the present embodiment, among the five scattered light apertures As, As1, As2 and As4 are scattered light guided to the light receiving element 56 by switching the position on the scattered light region K2 with respect to the X direction. Is changed with respect to the Y direction. In particular, in the present embodiment, the apertures As1, As2, and As4 are respectively switched to two positions that sandwich the optical axis L2 in the X direction. Thereby, the direction of the scattered light guided to the light receiving element 56 is switched to the opposite direction with respect to the Y direction by the displacement of the respective apertures As1, As2, and As4. Therefore, as described above, the orientation of the scattered light guided to the light receiving element 56 is changed for each aperture by switching the positions of the apertures As1, As2, and As4 on the scattered light region K2 to two different positions in the X direction. Can be switched to two different directions, that is, six different directions. Further, in the present embodiment, addition of apertures As3 and As5 arranged at the same position as the optical axis L2 with respect to the X direction, switching in eight directions is realized with a total of five apertures. As described above, in the present embodiment, the scattered light apertures As1, As2, and As4 are also used in scattered light imaging in two different directions, so that the number of apertures provided in the light shielding member 500 can be suppressed. As a result, an increase in size of the light shielding unit 54 and the entire apparatus is easily suppressed.

  Further, in order to shift the position of the scattered light aperture As in the X direction and the Y direction on the scattered light region K2, the driving unit 511 has a function of moving the light shielding member 500 in one direction. The function of moving in two dimensions is not necessarily required. Therefore, a two-dimensional shift of the aperture on the scattered light region K2 can be performed with a simple configuration. Further, the two-dimensional shift of the aperture on the scattered light region K2 can be realized by simpler drive control.

<Other optical systems>
The second photographing unit 200 is a unit for obtaining a fundus image (second fundus image) having a wider angle of view than the angle of view of the first photographing unit 100. The second fundus image is used, for example, as an image for position designation and position confirmation for obtaining the first fundus image. The second imaging unit 200 of the present embodiment preferably has a configuration capable of acquiring and observing a fundus image of the eye E to be examined in real time with a wide angle of view (for example, about 20 to 60 degrees). For example, as the second imaging unit 200, an observation / imaging optical system of an existing fundus camera and an optical system and a control system of a scanning laser ophthalmoscope (SLO) may be used.

  The anterior segment observation unit 700 is a unit that illuminates the anterior segment of the eye E with visible light and captures a front image of the anterior segment. An image captured by the anterior segment observation unit 700 is output to the monitor 850. The anterior ocular segment image acquired by the anterior ocular segment observation unit 700 is used for alignment between the imaging unit 500 and the eye E to be examined. The dichroic mirror 95 has a characteristic of transmitting the light beam from the second photographing unit 200 and reflecting the light beam from the anterior ocular segment observation unit 700.

  Next, the aberration detection optical system 110 will be described. The aberration detection optical system 110 includes a wavefront sensor 73. The aberration detection optical system 110 projects measurement light onto the fundus of the eye E, and receives (detects) the fundus reflection light of the measurement light as an index pattern image with the wavefront sensor 73. The aberration detection optical system 110 has a part of optical elements on the optical path of the first illumination optical system 100a and the first photographing optical system 100b (in the present embodiment, on the common optical path), and the optical paths of the optical systems 100a and 100b. Some are shared. That is, the aberration detection optical system 110 of the present embodiment shares the BS 71 to the concave mirror 45 arranged on the optical path of the optical systems 100a and 100b with the optical systems 100a and 100b. Further, the aberration detection optical system 110 includes a light source 76, a lens 77, PBS 78, BS 75, BS 71, a dichroic mirror 86, a PBS 85, a lens 84, a plane mirror 83, and a lens 82.

  The light source 76 emits measurement light. Measurement light from the light source 76 is reflected by the BS 75 through the lens 77 and the PBS 78. Thereby, the light from the light source 76 is guided to the optical path of the first illumination optical system 100a. As a result, the measurement light is condensed on the fundus of the eye E through the optical path of the first illumination optical system 100a.

  The measurement light is reflected at the condensing position of the fundus (for example, the retina surface). The fundus reflection light of the measurement light follows the optical path of the first illumination optical system 100a (that is, the optical path of the first photographing optical system 100b) in the opposite direction to that during projection. On the way, the measurement light is reflected by the wavefront compensation device 72. Thereafter, the measurement light is reflected by the BS 71, thereby deviating from the optical path of the first illumination optical system 100a. Thereafter, the measurement light is reflected by the dichroic mirror 86 and guided to the wavefront sensor 73 through the PBS 85, the lens 84, the plane mirror 83, and the lens 82.

  The wavefront sensor 73 receives fundus reflection light of measurement light for aberration measurement in order to detect wavefront aberration of the eye E. As the wavefront sensor 73, an element that can detect wavefront aberration including low-order aberration and high-order aberration (more specifically, a Hartmann Shack detector, a wavefront curvature sensor that detects a change in light intensity, and the like) is used. May be. The aberration information of the eye E detected by the wavefront sensor 73 is used to control the wavefront compensation device 72.

  The wavefront compensation device 72 is disposed in the optical path of the fundus imaging optical system 100 (in the present embodiment, in the common optical path of the fundus imaging optical system 100 and the aberration detection optical system 110). In the present embodiment, the reflection surface of the wavefront compensation device 72 is disposed at a position substantially conjugate with the pupil of the eye E to be examined. The wavefront compensation device 72 compensates the wavefront aberration of the eye E by controlling the wavefront of the incident light. For example, the wavefront compensation device 72 may be configured to compensate the wavefront by modulating the phase of the wavefront. Further, for example, a configuration in which the wavefront is compensated by giving an optical path length difference to each part of the wavefront may be employed. Moreover, the structure which uses both these methods together may be sufficient, and of course, another structure may be sufficient. More specifically, LCOS (Liquid Crystal On Silicon), MEMS (Micro Electro Mechanical Systems), and typically, a deformable mirror that is one form thereof may be used as the wavefront compensation device 72.

  In the above description, the light source 71 that emits light having a wavelength different from that of the light source 11 (first light source) for fundus photographing is used as the aberration detection light source. However, the light source 11 for fundus photography may also be used as a light source for detecting aberrations (that is, emitting measurement light).

  In the present embodiment described above, the wavefront sensor (more specifically, its microlens array) and the wavefront compensation device are used as the pupil conjugate of the eye E. It may be a conjugate position, and may be, for example, a corneal conjugate.

<Overview of control system>
Next, with reference to FIG. 6, a control system of the photographing apparatus 1 in the present embodiment will be described. The photographing apparatus 1 includes an arithmetic control unit 800 (hereinafter abbreviated as the control unit 800). The control unit 800 is a processor (for example, a CPU) that controls the entire apparatus of the photographing apparatus 1. In the present embodiment, a storage unit 801, an operation unit 802, and a monitor 850 are electrically connected to the control unit 800. The control unit 800 includes a light source 11, a scanning unit 25, a diopter correction unit 20, an astigmatism correction unit 30, a light receiving element 56, a wavefront compensation device 72, a wavefront sensor 73, a light source 76, a second imaging unit 200, and a deflection unit. 400, the drive mechanism 510, and the anterior ocular segment observation unit 700 are electrically connected.

  The storage unit 801 stores various control programs and fixed data. Further, the storage unit 801 may store an image captured by the imaging device 1, temporary data, and the like.

  The control unit 800 controls each member described above such as the first imaging unit 100 based on the operation signal output from the operation unit 802. The operation unit 802 may be a pointing device such as a touch panel or a mouse, or a keyboard. For example, the control unit 800 may display an aperture setting controller 860 (see FIG. 7) on the monitor 850. Then, the examiner may select the aperture arranged in the optical path of the first imaging optical system 100b from the scattered light aperture As and the confocal aperture Ac via the operation unit 802. . For example, the aperture setting controller 860 shown in FIG. 7 has a scattered light aperture setting button 862 and a confocal aperture setting button 861. When any one of the plurality of buttons is selected, an aperture corresponding to the selected button is arranged in the optical path of the first imaging optical system 100b. In the present embodiment, the aperture setting controller 860 may graphically indicate the type of aperture arranged in the optical path of the first imaging optical system 100b and the arrangement of the aperture with respect to the optical axis L2. For example, the control unit 800 may display the button selected by the examiner with identification information indicating that the button has been selected.

<Operation of the device>
Next, the operation of the photographing apparatus 1 having the above configuration will be described. The control unit 800 performs lighting of the light source 11 and two-dimensional scanning of the fundus by the scanning unit 25 and the deflecting unit 400. Then, the control unit 800 causes the monitor 850 to display the first fundus image formed based on the light reception signal output from the light receiving element 56 as a result of scanning. That is, the monitor 850 displays an observation image (live image) of the first fundus image. In the initial state, the confocal aperture Ac may be disposed on the optical axis L2. At this time, the control unit 800 may execute wavefront compensation control. That is, the control unit 800 performs projection of measurement light from the light source 76 and reception of light by the wavefront sensor 73 to detect the wavefront of the eye E, and further, based on the wavefront detection result, the aberration compensation unit 20, 30 and 72 may be driven. In addition, alignment is performed automatically or manually when photographing. For example, in manual alignment, the examiner operates a joystick (not shown) to irradiate the fundus of the subject's eye with laser light and drive the apparatus so that a desired image is displayed. In the present embodiment, for example, the alignment may be adjusted so that an image of a layer having blood vessels in the retina and the choroid can be obtained. After the alignment is completed, the first fundus image is captured (captured).

<Continuous shift shooting>
Continuous shift imaging is an imaging sequence in which the aperture position on the optical path is automatically switched to at least two different positions, and the first fundus image is captured for each aperture position. For example, confocal imaging performed by placing the confocal aperture Ac in the confocal optical path K1, and scattered light imaging performed by switching and arranging the scattered light aperture As at the eight positions in the scattered light optical path K2. , May be executed continuously. In this case, the control unit 800 causes the optical axis L2 to be sequentially arranged at positions of Pd, P0 °, P45 °, P90 °, P135 °, P180 °, P225 °, P270 °, and P315 °. Alternatively, the positions of the light shielding member 500 may be sequentially switched, and the first fundus image may be captured at each position. The first fundus image obtained as a result of imaging is stored in the storage unit 801. In this case, the images obtained by a series of continuous shift imaging may be associated with each other, for example, by storing them in the same folder or attaching common information to the image data. Further, the photographing results may be displayed side by side on the monitor 850 for each aperture position with respect to the optical axis L2.

<Vessel wall enhancement photography>
In the blood vessel wall-enhanced imaging, control is performed to shift the scattered light aperture As in a direction intersecting the direction of blood vessel travel acquired based on the first fundus image, and a new first fundus image is captured. This is a shooting sequence.

  The direction of blood vessel travel may be acquired, for example, by the control unit 800 performing blood vessel detection processing on the first fundus image and detecting the detection result. Further, the examiner who observed the first fundus image displayed on the monitor 850 inputs the direction of blood vessel travel to the apparatus via the operation unit 802, and the direction of blood vessel travel is controlled by the control unit as an input signal thereby. 800 may be acquired. For example, on the first fundus image of the monitor 850, the blood vessel traveling direction may be input by tracing the blood vessel whose blood vessel wall is to be emphasized with a pointing device or by selecting two points on the blood vessel. .

  In the present embodiment, the positioning control of the scattered light aperture As is performed so that the scattered light scattered in the direction close to the vertical direction with respect to the direction of blood vessel travel acquired by the control unit 800 is guided to the light receiving element 56. Is called. For example, when the direction of blood vessel travel is 30 ° obliquely, the scattered light aperture is located at one of the positions 135 ° and 315 ° close to the optical axis L2, which is nearly perpendicular to the oblique 30 °. Place. The control unit 800 may automatically capture (capture) the first fundus image based on the light reception signal from the light receiving element 56 after the positioning control of the scattered light aperture As. Thereby, in the blood vessel in which the traveling direction is acquired, the first fundus image in which the blood vessel wall on one side surface is emphasized (for example, the outer wall and the inner wall of the blood vessel wall are clarified) is stored in the storage unit. . Further, the control unit 800 may control the driving unit 511 to move the position of the scattered light aperture As to a position symmetrical to the imaging optical axis L2 (for example, from 135 ° to 315 °). Move). Then, the control unit 800 may further capture the first fundus image at the position after the movement. As a result, the first fundus image in which the blood vessel wall on the other side surface is emphasized is stored in the storage unit in the blood vessel for which the direction of blood vessel travel has been acquired. In this way, two types of first fundus images in which the blood vessel wall is emphasized on each side in the blood vessel from which the direction of blood vessel travel has been acquired can be acquired in a series of imaging sequences. Thereby, an image suitable for observation and analysis of the blood vessel wall can be efficiently captured.

  Further, the control unit 800 generates an image in which both sides of the blood vessel wall are emphasized (enhanced image in the present embodiment) by combining the two types of first fundus images in which the blood vessel wall is emphasized on each side. May be. For example, FIG. 8A shows a first fundus image in which the right-side blood vessel wall Wr is emphasized by arranging the disturbance light aperture As at a position of 0 °. FIG. 8B shows a first fundus image in which the left-side blood vessel wall Wl is emphasized by arranging the turbulent light aperture As at a position of 180 °. As a result of the synthesis of the two first fundus images, a synthesized image in which both the left and right blood vessel walls Wr and Wl are emphasized is obtained as shown in FIG. At the time of synthesis, the two types of first fundus images may be synthesized after being aligned with each other. Observation and analysis of the blood vessel wall can be performed more satisfactorily by the synthesized image.

<Manual shift shooting>
As described above, the examiner can manually select the position and type of the aperture arranged in the optical path (that is, K1 + K2) of the first imaging optical system 100b using the aperture setting controller 860. While checking the first fundus image displayed on the monitor 850, the examiner operates the operation unit 802 to select an aperture to be arranged on the optical path. Thereby, the aperture according to the selection of the examiner is arranged on the optical path. Then, by operating a photographing switch or the like, the control unit 800 causes the first fundus image to be photographed.

<Modification>
As mentioned above, although demonstrated based on embodiment, this indication is not limited to the said embodiment, A various deformation | transformation is possible.

  For example, in the above-described embodiment, each aperture is formed in one member (that is, the light shielding member 500), whereby the control unit 800 integrally controls the position of each aperture. However, it is not necessarily limited to this. For example, each aperture may be independently formed as a separate member. The position of each aperture may be integrally controlled by controlling such apertures to move with the same displacement amount and direction.

  Further, for example, in the above-described embodiment, the scattering direction of the scattered light guided to the light receiving element 56 using the five scattered light apertures As formed at different positions with respect to the direction orthogonal to the moving direction of the light shielding member 500 is expressed as follows: The case of switching from eight directions has been described. However, it is not necessarily limited to this. The light shielding member 500 may have a configuration in which less than five or more than five scattered light apertures are formed. For example, at least two of the apertures A1, As2, and As4 in the above embodiment are formed, and the control unit 800 displaces these two apertures at two positions on the scattered light optical path K2, respectively. Thus, the scattering direction of the scattered light guided to the light receiving element 56 may be switched to four different directions.

  Moreover, although the said embodiment demonstrated the case where the apertures A1, As2, and As4 were respectively displaced between two positions on the scattered light optical path K2, they may be respectively displaced between three or more positions. . Since the direction of the scattered light guided to the light receiving element 56 changes according to the positional relationship of the aperture with respect to the optical axis L2, the scattered light in a different direction can be selectively guided to the light receiving element 56.

  In the above embodiment, only one confocal aperture Ac is provided. As a result, the diameter of the confocal aperture Ac could not be changed. However, the present invention is not necessarily limited to this, and the imaging apparatus 1 may be configured to change the diameter of the confocal aperture Ac. In this case, a plurality of confocal apertures Ac having different diameters may be provided on the light shielding member 54 or the like. Then, by moving the light shielding member 54, the diameter of the confocal aperture Ac arranged in the confocal region K1 may be switched. As a result, bright field images having different appearances can be obtained.

  In the above embodiment, the case where the wavefront aberration of the eye E is measured using the wavefront sensor 73 provided in the optical system of the imaging apparatus 1 has been described. However, the imaging apparatus 1 only needs to have a configuration for measuring the wavefront aberration of the eye E based on the reflected light from the fundus, and the wavefront sensor 73 is not necessarily provided. For example, a case where the wavefront aberration is measured using the Phase Diversity method is conceivable. In this method, measurement light having a known wavefront aberration called Phase Diversity is intentionally given to a target optical system (here, eye E), and predetermined image processing is performed on an image obtained at that time. The wavefront aberration in the target optical system is estimated. In this case, for example, the light receiving element 56 provided in the fundus imaging optical system 100 can be used as a detector for wavefront aberration detection. That is, in this case, the fundus imaging optical system 100 can be shared with the aberration detection optical system 110. Of course, the detector may be provided separately from the light receiving element 56. Note that measurement light having Phase Diversity can be generated by controlling the wavefront compensation device 73 to a predetermined state, for example. Of course, it may be generated by other methods.

  In the above-described embodiment, the configuration for performing scattered light imaging in the apparatus with wavefront compensation is illustrated, but the present disclosure is not necessarily limited to the apparatus with wavefront compensation. For example, the configuration of the light shielding unit 54 and the control of the control unit 800 for the light shielding unit 54 may be applied to a fundus imaging apparatus that does not have wavefront compensation.

1 photographing device 56 light receiving element 100a first illumination optical system 100b first photographing optical system As scattered light aperture K fundus conjugate plane L1 photographing optical axis

Claims (10)

An irradiation optical system having an optical member for condensing laser light on the observation surface of the fundus and scanning means for two-dimensionally scanning the laser light with respect to the fundus, and the laser reflected by the fundus A photographing optical system that obtains a photographed image by receiving reflected light of the light with a light receiving element;
A plurality of apertures spaced from each other with respect to a first direction orthogonal to the imaging optical axis on the fundus conjugate plane of the imaging optical system;
Control means for integrally controlling the positions of the plurality of apertures,
The plurality of apertures includes at least a first aperture and a second aperture disposed at a position different from the first aperture with respect to a direction orthogonal to the first direction;
The control means moves the plurality of apertures in the first direction, and arranges the apertures arranged on the optical path of the scattered light scattered before and after the condensing point of the observation surface. Switching between two apertures, and further switching the positions of the first aperture and the second aperture on the optical path of the scattered light to two different positions with respect to the first direction, respectively, thereby guiding the light receiving element. A fundus imaging apparatus that switches the direction of scattered light in four different directions. The first aperture and the second aperture are formed in a positional relationship sandwiching the imaging optical axis with respect to the second direction,
The control means switches the aperture arranged on the optical path of the scattered light between the first aperture and the second aperture, thereby changing the direction of the scattered light guided to the light receiving element in the second direction. Switch in the opposite direction with respect to
Further, the scattered light guided to the light receiving element by switching the arrangement of the first aperture or the second aperture on the optical path of the scattered light to two positions sandwiching the imaging optical axis with respect to the first direction. The fundus imaging apparatus according to claim 1, wherein the direction is switched to an opposite direction with respect to the first direction. The plurality of apertures further includes a third aperture formed at the same position as the imaging optical axis in the second direction,
The control means switches the third aperture to two positions which are different from each other on the optical path of the scattered light and sandwich the photographing optical axis with respect to the first direction. The fundus photographing apparatus according to claim 2, wherein the direction of the guided scattered light is switched to two directions further different from the four directions. The plurality of apertures include a fourth aperture formed away from the imaging optical axis with respect to the second direction, and a fifth aperture disposed with the imaging optical axis sandwiched between the fourth aperture with respect to the second direction. Further including
The control means arranges the fourth aperture and the fifth aperture at the same position as the imaging optical axis with respect to the first direction on the optical path of the scattered light, and thereby the scattered light guided to the light receiving element. The fundus imaging apparatus according to claim 2 or 3, wherein the direction of the eye is switched to two directions further different from the four directions.   The fundus imaging apparatus according to claim 1, wherein the plurality of apertures are each formed as a circular opening having a small diameter with respect to a radius of the optical path.   The fundus imaging apparatus according to claim 1, wherein the control unit arranges an aperture arranged on the optical path among the plurality of apertures on a circumference centered on the imaging optical axis. The control means includes
Obtaining information on the running direction of blood vessels included in the captured image based on the captured image,
Positioning control of the plurality of apertures is performed so that the scattered light in the direction intersecting the acquired traveling direction is guided to the light receiving element, and a second light reception signal from the light receiving element after the positioning control is performed. The fundus imaging apparatus according to claim 1, wherein the captured image is captured. The first aperture and the second aperture are formed in a positional relationship sandwiching the imaging optical axis with respect to the second direction,
In the positioning control, when one of the first aperture and the second aperture is arranged on the optical path of the scattered light in the positioning control, the control means moves the other aperture to the scattered light after the captured image is captured. The fundus imaging apparatus according to claim 7, wherein the second positioning control is performed so as to be disposed on the optical path, and a third captured image based on a light reception signal from the light receiving element after the second positioning control is further captured.   The fundus imaging apparatus according to claim 8, wherein the control unit obtains an enhanced image in which a blood vessel wall is enhanced by synthesizing the second captured image and the third captured image. A wavefront compensation device that is disposed in the optical path of the imaging optical system and that controls the wavefront of incident light to compensate the wavefront aberration of the eye to be examined;
Wavefront aberration measuring means for measuring the wavefront aberration of the eye to be examined based on reflected light from the fundus;
Wavefront compensation device control means for driving the wavefront compensation device based on the wavefront aberration, and
The fundus imaging apparatus according to any one of claims 1 to 9, wherein a fundus image at a cell level by scattered light whose direction is limited by an aperture arranged on the optical path among the plurality of apertures is obtained as the captured image.