JP2010259606A - Ophthalmologic photographing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus capable of suppressing the projection of a fixation lamp in fluorescent photography and performing suitable observation. <P>SOLUTION: The ophthalmologic photographing apparatus includes an irradiation optical system provided with a light source part for emitting illumination light and a scanning part for two-dimensionally scanning the illumination light to a fundus and a light receiving optical system provided with a photodetector for receiving reflected light from the fundus illuminated by the illumination light, and obtains a fundus image on the basis of the light receiving signal of the photodetector. The light source part includes an excitation light source for emitting exciting light, that excites a contrast medium administered into the blood vessel of a subject to cause fluorescence emitted from the contrast medium, and a fixation light source for emitting visible light for guiding the fixation of the eye of the subject. The apparatus also includes a filter unit provided with a band-cut filter having optical characteristics which transmits the fluorescence and intercepts the exciting light and fixation light, which band-cut filter is disposed to be inserted and removed in the optical path of the light receiving optical system not shared with the illumination optical system. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an ophthalmologic imaging apparatus that performs fundus observation by scanning the fundus of a subject's eye with illumination light.

  2. Description of the Related Art Conventionally, an ophthalmologic photographing apparatus (scanning laser ophthalmoscope) that obtains a fundus image by scanning illumination light two-dimensionally with respect to the fundus using a scanning unit including a polygon mirror and a galvanometer mirror and receiving the reflection thereof. It is known (see, for example, Patent Document 1). In such an apparatus, while the fundus is scanned two-dimensionally with illumination light such as infrared light, visible light is turned on within the scanning range (for example, the center of the scanning range) to fixate the eye of the subject. Guided. Such an apparatus is used for fluorescence imaging in which a contrast medium is administered into a blood vessel of a subject and the fundus image is observed using a fundus image that emits fluorescence (fluorescence fundus image). In fluorescence imaging, illumination light that is visible light (for example, blue) is used as excitation light for a contrast agent, and a temporal change in the fundus is observed by capturing a plurality of fundus images in which fluorescence is generated by the excitation light. . In such a case, the fixation lamp for guiding fixation is always turned on during fluorescent photographing.

JP-A-2005-279122

  In fluorescence imaging, a contrast agent excited by illumination light emits light having a wavelength longer than that of excitation light and a broad band, but such fluorescence is compared with infrared light used in normal infrared fundus imaging. Since the light intensity is low, it is necessary to increase the sensitivity of the light receiving element in order to perform suitable photographing. However, if a fluorescent fundus image is obtained with the sensitivity of the light receiving element increased, the fixation lamp projected onto the fundus is reflected brightly in the center of the fundus, making it difficult to perform fundus observation suitably.

  In view of the above-described problems, an object of the present invention is to provide an ophthalmologic photographing apparatus capable of suppressing a reflection of a fixation lamp in a fundus image and performing suitable observation in fluorescent photographing.

In order to solve the above problems, the present invention is characterized by having the following configuration.
(1) An irradiation optical system having a light source unit that emits illumination light having different wavelengths, a scanning unit that scans the illumination light two-dimensionally with respect to the fundus, and a fundus illuminated by the illumination light. A light receiving optical system having a light receiving element for receiving reflected light, and obtaining a fundus image based on a light reception signal of the light receiving element, wherein the light source unit is placed in a blood vessel of the subject. An excitation light source that emits excitation light that excites the administered contrast agent and emits fluorescence from the contrast agent; and a fixation light source that emits visible light to induce fixation of the subject's eye, A filter unit having a band cut filter having an optical characteristic of transmitting the fluorescence and blocking the excitation light and fixation light, wherein the band cut filter is disposed in an optical path of the light receiving optical system that is not shared with the illumination optical system. And a filter unit that is detachably arranged.
(2) In the ophthalmologic photographing apparatus according to (1), the band cut filter includes a first filter layer having an optical characteristic that blocks the excitation light and transmits the fluorescence, and blocks the fixation light. And a second filter layer having an optical characteristic of transmitting fluorescence.
(3) In the ophthalmologic photographing apparatus according to (2), the band cut filter includes:
A first substrate on which the first filter layer is formed, and a second substrate different from the first substrate, the second substrate on which the second filter layer is formed.
(4) In the ophthalmologic photographing apparatus according to any one of (1) to (3), the light source unit further includes an infrared light source that emits infrared light, and infrared light is emitted from the light source unit to emit infrared light. Mode switching means for switching between an infrared imaging mode for obtaining a fundus image and a fluorescence imaging mode for obtaining the fluorescent fundus image by emitting the excitation light from the light source unit, and the filter unit includes the mode The band cut filter is inserted into the optical axis based on the setting by the switching means.
(5) In the ophthalmologic photographing apparatus according to any one of (1) to (4), the excitation light source emits blue laser light, the fixation light source emits red light, and the band cut filter The laser light and the red light are blocked, and the fluorescence having a longer wavelength than the laser light is transmitted.
(6) In the ophthalmologic photographing apparatus according to any one of (1) to (5), the excitation light source emits 490 nm laser light, the fixation light source emits 660 nm laser light, and the band cut filter Is characterized by blocking visible light having a bandwidth as narrow as possible at the wavelength center of 660 nm while transmitting visible light having a wavelength longer than 490 nm.

  According to the present invention, it is possible to suppress a reflection of a fixation lamp in a fundus image in fluorescence photography and perform suitable observation.

  Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing an optical system of a scanning laser ophthalmoscope as an embodiment of an ophthalmologic photographing apparatus. The scanning laser ophthalmoscope includes a laser light scanning unit 50 that two-dimensionally scans the fundus with observation laser light (illumination light), and irradiates the fundus with laser light emitted from the light source unit 100. The irradiation optical system 60 and the light receiving optical system 70 that receives the laser light reflected from the fundus via the laser light scanning unit 50 are roughly classified.

  The observation laser light for illuminating the fundus of the subject's eye E is emitted from the light source unit 100 and irradiated onto the fundus by the irradiation optical system 60. In the present embodiment, the light source unit 100 is configured to be able to emit illumination light (here, laser light) having three different wavelengths. Specifically, a semiconductor laser light source (LD) 101 which is an infrared light source that emits near-infrared laser light (for example, wavelength λ = 790 nm), and a semiconductor laser that emits red laser light (for example, wavelength λ = 660 nm). And a semiconductor laser light source 103 that emits blue laser light (for example, wavelength λ = 490 nm). In the present embodiment, red laser light is used as fixation light, and blue laser light is used as excitation light at the time of fluorescence imaging. The illumination light is not limited to laser light. An SLD (Super Luminescent Diode) may be used as the light source.

  Dichroic mirrors are respectively arranged on the outgoing optical axes of the respective light sources so that the respective laser beams are coaxial. Specifically, a dichroic mirror 105 that transmits near-infrared light and reflects light of other wavelengths (visible light) is reflected in front of the light source 101, and red light is reflected in front of the light source 102 and has a wavelength greater than that of red. A dichroic mirror 106 that transmits light of a short color (blue) is disposed.

  These dichroic mirrors 105 and 106 are arranged so that the laser beams emitted from the respective laser light sources are coaxial, and as shown in the figure, each laser beam is transmitted or reflected by the dichroic mirror, and the irradiation optical system 60. To the optical axis L1. The respective laser beams that are coaxial in this way are guided to the fundus by the optical member of the irradiation optical system 60.

  The light sources 101 to 103 are each controlled to emit laser light. For this reason, from the light source part 100, a several laser beam is radiate | emitted simultaneously, or only a specific laser beam is radiate | emitted. For example, when performing fundus observation or fundus photographing using infrared light using the light source 101, lighting control is performed so that the light source 102 is turned on at a predetermined scanning position in the scanning range of the infrared laser light and is turned off at other scanning positions. Is performed to induce fixation of the subject. Similarly, fixation guidance is performed by turning on and off the light source 102 for fluorescent fundus photographing using excitation light using the light source 103.

  The irradiation optical system 60 includes a light source unit 100, a hall mirror (aperture mirror) 2 having an opening in the center, a lens 3, mirrors 4 and 5, concave mirrors 6, 8 and 10, a polygon mirror 7, and a galvanometer mirror 9. . The hall mirror 2 has a role of narrowing the beam diameter of the laser beam having the optical axis L1. The mirrors 4 and 5 can be moved in the arrow direction (optical axis direction) shown in FIG. 1 by driving means (not shown), and focusing (diopter correction) can be performed by changing the optical path length. The polygon mirror 7 is an optical member for causing the laser light to scan in the horizontal direction with respect to the fundus of the subject's eye E, and the galvanometer mirror 9 emits the laser light in a direction perpendicular to the scanning direction by the polygon mirror 7. Plays the role of scanning. These optical members constitute a laser beam scanning unit 50 for two-dimensionally scanning the laser beam emitted from the light source unit 100 with respect to the subject's fundus.

  The laser light emitted from the light source unit 100 passes through the opening of the hall mirror 2, passes through the lens 3, is reflected by the mirror 4, the mirror 5, and the concave mirror 6, and travels toward the polygon mirror 7. The light beam reflected by the polygon mirror 7 is reflected by the concave mirror 8, the galvano mirror 9, and the concave mirror 10, and then condensed on the fundus of the subject's eye and is two-dimensionally (XY shown in the figure). Scanned in the axial direction).

  Next, the configuration of the light receiving optical system 70 will be described. The light receiving optical system 70 shares the concave mirror 10 to the hall mirror 2 of the irradiation optical system 60, and includes a filter unit 90, a lens 12, a pinhole plate 13 having a pinhole on the optical axis, a condensing lens 14, and red. A light receiving element 15 having sensitivity from the outer region to the visible light region is provided. The pinhole plate 13 is arranged at a position conjugate with the observation point (imaging point) of the subject's fundus. Further, an APD (avalanche photodiode) capable of receiving (detecting) laser beams having three different wavelengths emitted from the light source unit 100 is used for the light receiving element 15 of the present embodiment. Here, an optical axis that does not share an optical path with the irradiation optical system 60 in the light receiving optical system 70 is L2.

  The reflected light of the laser beam scanned on the fundus of the subject's eye follows the irradiation optical system 60 described above in reverse, is reflected by the Hall mirror 2, and is bent downward in the drawing. Note that the pupil position of the subject's eye and the opening of the hall mirror 2 are conjugated by the lens 3 and the concave mirrors 6, 8, and 10. The reflected light reflected by the hall mirror 2 and passing on the optical axis L2 passes through the filter unit 90, and then focuses on the pinhole of the pinhole plate 13 via the lens 12. The reflected light focused at the pinhole is received by the light receiving element 15 through the condenser lens 14.

  Next, the configuration of the filter unit 90 will be described. The filter unit 90 includes a band cut filter 90A, a holder 93 that holds the band cut filter 90A, and a drive unit 95 that arranges the band cut filter 90A held by the holder 93 so as to be detachable from the optical axis L2. Note that the band cut filter 90 </ b> A of the present embodiment includes two filters, a first filter 91 and a second filter 92.

  FIG. 2 is a schematic diagram illustrating the optical characteristics of the filter that the filter unit 90 has. Here, FIG. 2A shows the overall optical characteristics of the band cut filter 90A, FIG. 2B shows the optical characteristics of the first filter 91, and FIG. 2C shows the optical characteristics of the second filter 92. FIG. In the graph, the horizontal axis represents wavelength and the vertical axis represents transmittance. The band-cut filter 90A is composed of two filters disposed on the optical axis L2 at the time of fluorescent fundus photographing, and as a whole, blue laser light (wavelength 490 nm) as excitation light and red laser light (wavelength 660 nm) as fixation light. The filter has an optical characteristic that blocks light having a wavelength of) and transmits fluorescence from the fundus. The fluorescence here refers to light generated by fluorescence emission of the contrast agent by irradiating excitation light to the blood vessel of the fundus oculi contrasted by the contrast agent administered to the blood vessel of the subject.

  As shown in FIG. 2A, the band cut filter 90A has an optical characteristic of blocking light (excitation light) having a wavelength of 490 nm and transmitting light having a predetermined long wavelength from 490 nm. Specifically, the transmittance of light having a wavelength up to +30 nm, preferably up to about +5 nm on the long wavelength side is reduced or the light of the light emitted from the excitation light source 103 is adjusted to correspond to the variation in wavelength of the emitted light. Shut off. Thereby, excitation light (reflected light at the fundus) is hardly incident on the light receiving element 15, and fluorescence by the excitation light is incident on the light receiving element 15 and received.

  The band cut filter 90A further blocks light having a wavelength of 660 nm (fixation light) and has a blocking band width of a predetermined width centering on 660 nm. A narrower band width for blocking fixation light is more preferable. Specifically, it is configured to have as narrow a bandwidth as possible with the wavelength of the light emitted from the fixation light source 102 as the center wavelength while transmitting fluorescence as much as possible. More preferably, the bandwidth having the wavelength of the fixation light source 102 as the center wavelength has a bandwidth of about ± 30 nm, preferably ± 5 nm, so as to correspond to variations in the fixation light source 102. Thereby, the fixation light included in the fluorescence wavelength region is not incident on the light receiving element 15, and the fluorescence excluding the cutoff band width of the fixation light wavelength is incident on the light receiving element 15 and received.

  Due to such optical characteristics, the band cut filter 90A can block fixation light and excitation light reflected from the fundus and transmit fluorescence as much as possible.

  A more detailed configuration of the band cut filter 90A having such optical characteristics will be described. In the present embodiment, the first filter layer having an optical characteristic that transmits light having a wavelength longer than the excitation light, and the second filter characteristic having an optical characteristic that blocks fixation light and transmits light having a wavelength other than the fixation light. The band cut filter 90A is obtained by combining the filter layer. In the present embodiment, the first filter 91 made of a transparent substrate on which the first filter layer is formed and the second filter 92 having a second filter layer formed on a transparent substrate different from the first filter 91 are used to cut the band. A filter 90A is formed.

  The optical characteristic of the first filter 91 shown in FIG. 2B has an optical characteristic that blocks excitation light and transmits light (fluorescence) having a wavelength longer than that of the excitation light. Moreover, the optical characteristic of the second filter 92 shown in FIG. 2C has an optical characteristic that blocks fixation light and transmits light having a wavelength other than the fixation light. Such first filter layer and second filter layer are formed by the following method.

  By preparing a substrate (for example, a transparent glass substrate) that transmits light such as glass, and forming a multilayer film of a predetermined coating material on the substrate using a vacuum deposition method, a sputtering method, an ion beam sputtering method, or the like, A filter with the desired optical properties is obtained.

  Coding materials include high refractive index metal oxides such as titania (titanium dioxide) and tantala (tantalum pentoxide), which have a high refractive index to the substrate, and silica (silicon dioxide), which has a low refractive index to the substrate. ) Or the like is used. These metal oxides having different refractive indexes are alternately laminated on the substrate to obtain a multilayer film. At this time, the thickness of one film (metal thin film) is set to about a quarter of the wavelength to be cut off, and is set to a thickness of about several tens nm to several hundreds nm by design. Such a thin film is laminated | stacked about several to 100 layers until the desired optical characteristic is acquired, and each filter layer is obtained.

  By the above coating method, the 1st filter 91 in which the 1st filter layer was formed, and the 2nd filter 92 in which the 2nd filter layer was formed are obtained.

Next, the control system will be described. FIG. 3 is a block diagram showing a control system of the scanning laser ophthalmoscope in the present embodiment. The control unit 30 is a member that controls the entire apparatus, and is a CPU or the like. The control unit 30 includes a light source unit 100 (light sources 101 to 103), a polygon mirror 7, a galvano mirror 9, a light receiving element 15, drive means (not shown) for driving the mirrors 4 and 5, various condition settings, A control unit 32 for operating the apparatus, an image processing unit 33 for forming a fundus image of the subject's eye based on a signal received by the light receiving element 15, a drive unit 95, and the like are connected. The monitor 34 displays the fundus image formed by the image processing unit 33. The control unit 30 is connected to a storage unit 35 for storing various information. Note that the storage unit 35 has a fixed number of information necessary for image formation such as the number of reflecting surfaces (mirrors) of the polygon mirror used and image lines for constructing a fundus image, and two-dimensional scanning of illumination light. Information such as the position (timing) at which the illumination light is turned on is stored. Here, the fixation light is set to be lit at the center of the scanning range.

  The control unit 32 is provided with an infrared imaging mode switch 32a and a fluorescence imaging mode switch 32b, which are mode changeover switches for setting the imaging mode. When the infrared photographing mode is set by the infrared photographing mode switch 32a, the control unit 30 drives the light source 101 and controls the driving unit 95 to remove the band cut filter 90A from the optical axis L2. Similarly, when the fluorescence imaging mode is set by the fluorescence imaging mode 32b, the control unit 30 drives the light source 103 and controls the drive unit 95 to place the band cut filter 90A on the optical axis L2. When the fluorescent photographing mode is set, the control unit 30 improves the sensitivity of the light receiving element 15.

  The operation of the scanning laser ophthalmoscope having the above configuration will be described. The examiner aligns the apparatus main body with the eye of the subject using a joystick (not shown). Then, the examiner drives the mirrors 4 and 5 using the driving means to correct the diopter. With the diopter corrected, the examiner moves the apparatus using a joystick (not shown) so that the fundus of the subject's eye is irradiated with laser light so that a desired image is displayed on the monitor 34. , Align. In addition, the examiner uses the control unit 32 to set the photographing mode.

  When imaging is started by the examiner's operation, the control unit 30 causes the light source 101 to emit infrared laser light under the control of the light source 100. The laser beam that has passed through the Hall mirror 2 is scanned by the polygon mirror 7 and further scanned in the vertical direction (from top to bottom) by driving the galvanometer mirror 9. Near-infrared laser light reflected by the galvanometer mirror 9 is condensed on the fundus and scanned two-dimensionally. At this time, the control unit 30 performs control to turn on the light source 102 and turn it off at other scanning positions at the center position in the range scanned by the polygon mirror 7 and the galvanometer mirror 9, and present fixation light to the subject. To do. The reflected light of the laser beam condensed on the fundus is received by the light receiving element 15 through the photographing optical system.

  FIG. 4 is a schematic diagram of a fundus image displayed on the monitor 34. FIG. 4 is for explaining the display of the fundus image, and is not limited to either the infrared fundus image or the fluorescent fundus image.

  The image processing unit 33 sequentially arranges the received light signals from the light receiving element 15 obtained by the reflected light from the fundus in the scanning range as image data, and in a row in the horizontal direction from the top to the bottom in the display area 34a of the monitor 34. Display in order. In this way, image line data for one column in the display area 34 a is obtained by the rotation of the polygon mirror 7. The image processing unit 33 displays the acquired image line data for one column in a row one row below the previously displayed image line data for one column. The control unit 30 and the image processing unit 33 sequentially perform such processing for the number of image lines stored in advance in the storage unit 25, thereby reducing the imaging range of the subject's fundus scanned in two dimensions. It is displayed on the monitor 34 as a single image (image for one frame). Then, the control unit 30 returns the galvanometer mirror 9 to the reflection angle at the start of scanning, and similarly controls the drive so that the laser beam is scanned again from the top to the bottom. This frame rate is about 10 to 30.

  In this way, a fundus image as shown in FIG. 4 is obtained. At this time, the scanning range of the laser beam corresponds to the display area 34a.

  In the laser scanning, the control unit 30 performs control to turn on the light source 102 (emit laser light) at a predetermined scanning position. In FIG. 4, control is performed so that fixation laser light is emitted at a scanning angle corresponding to the center of the display area 34 a, but the present invention is not limited to this. The position of the fixation laser light irradiated to the fundus can be appropriately changed using the switch.

  Next, the operation of the filter unit 90 in each shooting mode will be described. The examiner sets the infrared imaging mode by the infrared imaging mode switch 32a of the control unit 32. Based on this setting, the control unit 30 adjusts the sensitivity of the light receiving element 15 so that the reflected light of the infrared laser light applied to the fundus can be received so that a sufficient fundus image can be obtained. When the infrared imaging mode is set, the band cut filter 90A is removed from the optical path. The control unit 30 controls the light source 101 to emit infrared laser light having sufficient light intensity for photographing. At the same time, the control unit 30 controls the light source 102 so that the fixation light is turned on at a predetermined position in the scanning range. At this time, the light intensity of the fixation laser light emitted from the light source 102 is set to be weaker than the infrared laser light emitted for photographing (however, the visible light intensity). The infrared fundus image of the subject's eye that is fixedly guided is displayed on the monitor 34 and stored in the storage unit 35. Note that the light intensity of the visible laser light for fixation is relatively weaker than that of the infrared laser light, and the light receiving element also receives light using a light receiving sensitivity that matches the light intensity of the infrared laser light. The fixation laser beam is difficult to be reflected in the obtained fundus image.

  Next, the case of the fluorescence imaging mode will be described. In fluorescence imaging, a fluorescence fundus image in a state in which a contrast medium (for example, fluorescein) is administered into the blood vessel of a subject in advance or in a state of being administered is captured. The fluorescent photographing mode is set by the examiner using the fluorescent photographing mode switch 32b. Based on this setting, the control unit 30 drives the drive unit 95 to arrange (insert) the band cut filter 90A on the optical axis L2. At the same time, control for increasing the light receiving sensitivity of the light receiving element 15 is performed. The light receiving sensitivity of the light receiving element 15 is set to such a sensitivity that fluorescent light with low light intensity is suitably received. Further, the light source 103 is controlled to emit blue laser light. Then, the apparatus is aligned by the examiner and fluorescence imaging is started. At this time, the control unit 30 controls the light source 102 in the same manner as the infrared imaging mode, and emits a fixation laser beam at a predetermined scanning position. Fluorescence and fixation fundus reflected light emitted from the contrast medium excited by the blue laser light is guided to the light receiving optical system 70 as described above, passes through the band cut filter 90A, and then received by the light receiving element 15. Received light. At this time, the fixation light (the reflected light thereof) is blocked by the band cut filter 90A, and most of the fluorescence is transmitted. Information received by the light receiving element 15 is imaged as described above. In this way, a fluorescent fundus image with reduced influence (reflection) of the fixation light is obtained. The fluorescent fundus image is displayed on the monitor 34 and stored in the storage unit 35. The fundus observation of the subject's eye can be preferably performed by the fluorescent fundus image in which the fixation light is reduced.

  Note that the scanning laser ophthalmoscope used in the present embodiment has an excellent function of observing the fundus as a moving image, and is preferable for temporal observation of blood vessels that are gradually contrasted with a contrast agent. In the present invention, since the band cut filter 90A is arranged on the optical axis L2, the influence of the fixation light can be reduced without changing the frame rate of the apparatus, and suitable fundus observation can be performed. In the present invention described above, it is not necessary to control lighting of the fixation light source in order to suppress the reflection of fixation light, and a fluorescence fundus image can be obtained without reducing the frame rate. Specifically, when the band cut filter is not used, the fluorescence fundus image is displayed when the fixation light is turned off while the fixation light is turned on at a sufficient interval to guide the fixation of the subject. It is set as the structure to obtain. In this case, the frame rate is lower than that in the infrared photographing mode, the moving image performance of the fluorescent fundus image is lowered, and the accuracy of fundus observation is lowered.

  In the above-described embodiment, the filter unit is controlled by the setting of the shooting mode switch and the band cut filter is inserted / removed. However, the present invention is not limited to this. The examiner may manually operate the filter unit to insert / remove the band cut filter.

  In the above-described embodiment, the light source unit is provided with a light source that emits infrared light, fixation light, and excitation light. However, the present invention is not limited to this. The present invention can be applied to any ophthalmologic photographing apparatus for fluorescence photographing that includes a light source that emits at least excitation light and fixation light.

  In the embodiment described above, the excitation light is blue light of 490 nm and the fixation light is red light of 660 nm. However, the present invention is not limited to this. The fixation light may be visible light that can be visually recognized by the subject, and may be other colors or other wavelengths. Moreover, since excitation light respond | corresponds to a contrast agent, it is good also as a different wavelength from this embodiment by the contrast agent used for a fluorescence contrast.

  In the present embodiment described above, the band cut filter has an optical specification that blocks excitation light and fixation light, but is not limited thereto. The fluorescent fundus image may be configured so that the influence of the fixation light can be reduced and the fundus observation can be suitably performed. The band cut filter may have, for example, an optical characteristic that transmits a part of fixation light or an optical characteristic that transmits a part of excitation light.

  In the above-described embodiment, the band cut filter is configured by a combination of the first filter and the second filter. However, the present invention is not limited to this. For example, after forming the first filter layer on one side of the substrate, the second filter layer may be formed on the first filter layer. Further, the first filter layer may be formed on the second filter layer. In this case, a band cut filter can be obtained with a single substrate. Further, since it is not necessary to move the substrate during coating, man-hours can be reduced. When two filter layers are used in such a manner as described above, it is preferable to provide a coating for buffering stress between the first filter layer and the second filter layer. Moreover, you may form a 1st filter layer and a 2nd filter layer in the surface and the back surface of a board | substrate, respectively.

It is the figure which showed the optical system of the ophthalmologic imaging device of this embodiment. It is a schematic diagram which shows the optical characteristic of a band cut filter. It is the block diagram which showed the control system of the ophthalmologic imaging device in this embodiment. It is a figure explaining the image displayed on a monitor.

DESCRIPTION OF SYMBOLS 1 Light source 7 Polygon mirror 9 Galvanometer mirror 15 Light receiving element 34 Monitor 50 Laser beam scanning part 60 Irradiation optical system 70 Light reception optical system 90 Filter unit 90A Band cut filter 100 Light source part

Claims (6)

An irradiation optical system having a light source unit that emits illumination light having different wavelengths, a scanning unit that scans the fundus in two dimensions, and reflected light from the fundus illuminated by the illumination light; A light receiving optical system having a light receiving element for receiving light, and an ophthalmologic photographing apparatus for obtaining a fundus image based on a light reception signal of the light receiving element.
The light source unit includes an excitation light source that emits excitation light that excites a contrast agent administered into a blood vessel of the subject and emits fluorescence from the contrast agent, and a visible light that induces fixation of the subject's eye. A fixation light source that emits light, and
A filter unit having a band cut filter having an optical characteristic of transmitting the fluorescence and blocking the excitation light and fixation light, wherein the band cut filter is disposed in an optical path of the light receiving optical system that is not shared with the illumination optical system. A filter unit arranged to be detachable,
An ophthalmologic photographing apparatus comprising: The ophthalmologic photographing apparatus according to claim 1.
The band cut filter is
A first filter layer having an optical property of blocking the excitation light and transmitting the fluorescence;
A second filter layer having an optical property of blocking the fixation light and transmitting at least the fluorescence;
An ophthalmologic photographing apparatus comprising: The ophthalmologic photographing apparatus according to claim 2,
The band cut filter is
A first substrate on which the first filter layer is formed;
A second substrate different from the first substrate, the second substrate having the second filter layer formed thereon;
And an ophthalmologic photographing apparatus. In the ophthalmologic photographing apparatus according to any one of claims 1 to 3,
The light source unit further includes an infrared light source that emits infrared light,
A mode for switching between an infrared imaging mode in which infrared light is emitted from the light source unit to obtain an infrared fundus image, and a fluorescence imaging mode in which the excitation light is emitted from the light source unit to obtain a fluorescent fundus image Switching means,
The ophthalmologic photographing apparatus according to claim 1, wherein the filter unit inserts the band cut filter into the optical axis based on a setting by the mode switching means. In the ophthalmologic photographing apparatus according to any one of claims 1 to 4,
The excitation light source emits blue laser light,
The ophthalmic imaging apparatus, wherein the fixation light source emits red light, and the band cut filter blocks the laser light and the red light and transmits the fluorescence having a longer wavelength than the laser light. 6. The ophthalmologic photographing apparatus according to claim 1, wherein the excitation light source emits a laser beam of 490 nm, the fixation light source emits a laser beam of 660 nm, and the band cut filter is larger than 490 nm. An ophthalmologic photographing apparatus characterized by blocking visible light having a narrow bandwidth as much as possible at a wavelength center of 660 nm while transmitting visible light having a long wavelength.