JP6776777B2 - Fundus photography device - Google Patents

Description

The present invention relates to a fundus photography apparatus.

Conventionally, as a fundus photography device, a device for obtaining an image of the fundus by scanning light with an optical scanner on the fundus of the eye to be inspected has been known. For example, a scanning laser ophthalmoscope (SLO) obtains a frontal image of the fundus as a result of scanning on the fundus.

In such a fundus imaging device, attempts have been made to photograph a wide area of the fundus (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2014-138904

However, there is room for improvement in the optical system of the device that captures a wide area of the fundus by scanning. For example, the difference in aberration for each scanning position tends to affect the image. Further, as in Patent Document 1, when the objective optical system for widening the scanning range is composed of a lens system, reflection from the lens surface may affect the image.

In view of at least one of the problems of the prior art, the present disclosure has a technical problem of providing a fundus photography apparatus provided with a new optical system capable of satisfactorily photographing a wide range of the fundus.

The fundus imaging apparatus according to the first aspect of the present disclosure includes a scanning optical system having an optical scanner that changes the traveling direction of the light in order to scan the light from the light source on the fundus of the eye to be inspected, the optical scanner, and the subject. A fundus imaging apparatus which is arranged between the eye examination and has an objective optical system for guiding the light from the optical scanner to the fundus, and forms an image of the fundus based on the reflected light of the fundus of the light. The objective optical system includes a first mirror that reflects the light from the optical scanner to form a first turning point at which the light is swiveled in accordance with the operation of the optical scanner. It has a second mirror that forms a second turning point at which the light emitted to the eye to be examined is swirled by further reflecting the light reflected by the first mirror, and the second turning point. The swing angle of the light incident on the first mirror is smaller than the swing angle of the light in the above.

According to the present disclosure, a wide area of the fundus can be satisfactorily photographed.

It is a figure which shows the schematic structure of the optical system in the fundus photography apparatus of this embodiment. It is a figure which showed the objective optical system which concerns on 1st Example. It is a block diagram which showed the electrical structure of the fundus photography apparatus which concerns on 1st Example. It is a figure which showed the objective optical system which concerns on 2nd Example. It is a figure which showed the objective optical system which concerns on 3rd Example.

Hereinafter, typical embodiments in the present disclosure will be described with reference to the drawings.

First, the outline of the fundus photography apparatus (hereinafter abbreviated as “imaging apparatus”) according to the present disclosure will be described with reference to FIGS. 1 and 2. The imaging device 100 obtains an image of the fundus by scanning the light on the fundus of the eye E to be inspected. The image of the fundus may be a frontal image or a tomographic image. In the photographing apparatus 100 of the present disclosure, the scanning range of light in the fundus may be wide. For example, light may be scanned in a range of 100 ° or more in full-width, and an image within the scanning range may be obtained.

As shown in FIG. 1, the photographing apparatus 100 includes a scanning optical system 1 and an objective optical system 2. Further, the photographing apparatus 100 has light receiving optical systems 10a and 20a. The scanning optical system 1 includes optical scanners 15 and 27 that change the traveling direction of the light in order to scan the light from the light source on the fundus Er. Further, the objective optical system 2 is arranged between the scanning optical system 1 (more specifically, the optical scanners 15 and 27) and the eye E to be inspected. The objective optical system 2 is used to guide the light from the optical scanners 15 and 27 to the fundus Er. The light guided to the fundus Er by the objective optical system 2 is reflected and scattered by the fundus Er and is emitted from the pupil. The light emitted from the pupil is received by the detectors 18 and 31 included in the light receiving optical systems 10a and 20a. As a result, an image of the fundus is formed based on the received light signals output from the detectors 18 and 31. The detectors 18 and 31 may be provided in, for example, the scanning optical system 1.

The scanning optical system 1 may have one of the SLO optical system 10 and the OCT optical system 20. Further, as shown in FIG. 1, both may be provided. The SLO optical system 10 has an optical scanner 15 and is used to obtain a frontal image of the fundus Er. The SLO optical system 10 may be a line scan SLO optical system that scans the fundus Er by scanning a line-shaped light beam in at least one direction with the optical scanner 15, or a point-shaped light beam may be scanned by the optical scanner 15. It may be a point scan SLO optical system that scans two-dimensionally with. Further, the OCT optical system 20 has an optical scanner 27, and by scanning the measurement light on the fundus Er using the optical scanner 27, a tomographic image of the fundus Er is obtained non-invasively by using the technique of optical interference. .. In the present embodiment, the optical scanners 15 and 27 have a positional relationship conjugate with the anterior segment of the eye E to be inspected with respect to the objective optical system 2. In the present disclosure, "conjugate" is not necessarily limited to a perfect conjugate relationship. In the present disclosure, the "conjugate" relationship may be a perfect conjugate relationship or a positional relationship deviating from the perfect conjugate relationship within the permissible range of accuracy.

As shown in FIG. 1, in a configuration in which the scanning optical system 1 includes both the SLO optical system 10 and the OCT optical system 20, the scanning optical system 1 includes the optical path of the SLO optical system 10 and the OCT optical system 20. It may have an optical path coupling member 40 that couples with an optical path. The wavelength of the light emitted from the light source 11 of the SLO optical system 10 and the wavelength of the light emitted from the light source 21 of the OCT optical system 20 are different from each other, and the optical path coupling member 40 has a wavelength-selective optical path. It is preferable to use a dichroic mirror that combines the above. However, the present invention is not limited to this, and other optical path coupling members such as a half mirror may be used. In FIG. 1, the optical path coupling member 40 couples the optical paths of the SLO optical system 10 and the OCT optical system 20 between the optical scanner of each optical system and the objective optical system 2. As described above, in the present embodiment, the SLO optical system 10 and the OCT optical system 20 are individually provided with optical scanners. As a result, for example, it becomes easy to obtain a tomographic image at an arbitrary position in parallel with the acquisition of the front image.
In the light receiving optical system 10a, the fundus reflected light of the light emitted from the SLO optical system 10 is received by the detector 18. Further, in the light receiving optical system 20a, the fundus reflected light of the light (measurement light) emitted by the OCT optical system 20 is combined with the reference light and then received by the detector 31.

The objective optical system 2 is a turning point (this embodiment) in which light is swirled around the anterior segment of the eye E to be inspected (for example, the pupil region) through the optical scanners 15 and 27 as the optical scanners 15 and 27 operate. The second turning point) in the form is formed. As shown in FIG. 2, the objective optical system 2 may be a mirror system that does not include a lens element. In this case, the influence of noise (for example, flare in the front image) by the objective optical system 2 on the image of the fundus can be suppressed.

The objective optical system 2 includes at least a first mirror 50 and a second mirror 60. As shown in FIG. 2, the objective optical system 2 in the present embodiment may have an optical member such as a mirror in addition to the first mirror 50 and the second mirror 60.

In the present embodiment, the first mirror 50 is arranged between the scanning optical system 1 and the second mirror 60. Light from the optical scanners 15 and 27 is incident on the first mirror 50, and the incident light is relayed to the second mirror 60.

In the present embodiment, the first mirror 50 reflects the light from the optical scanners 15 and 27, so that the light (specifically, the light reflected by the first mirror) rotates with the operation of the optical scanners 15 and 27. A first turning point (indicated by reference numeral r1 in FIG. 2) is formed.

In this embodiment, the first mirror 50 is a focused mirror and has positive or negative power. The first mirror 50 forms the first turning point at the focal point of the first mirror 50.

Such a first mirror 50 is preferably an aspherical mirror whose mirror surface is formed by a quadric surface. The quadric surface consists of a locus obtained by rotating a quadric curve (also called a conic section) around an axis of symmetry. As the first mirror 50 having a quadric curved surface, for example, the aspherical mirror may be at least one of a parabolic mirror, a double-sided mirror, and an ellipsoidal mirror. However, the first mirror 50 may have a shape other than an aspherical mirror whose mirror surface is a quadric surface. For example, it may be a spherical mirror, and other shapes are also conceivable. Further, although the first mirror 50 in the present embodiment is one mirror, it may be replaced with a combination of a plurality of mirrors.

The second mirror 60 has a positive power. The second mirror 60 further reflects the light reflected by the first mirror 50 to form a second turning point in which the light emitted from the objective optical system 2 to the eye E to be inspected is swirled.

In the present embodiment, in the second mirror 60, the eye E to be inspected having two focal points r1 and r2 is arranged at one of the focal points r2. More specifically, the anterior segment of the eye (eg, the position of the pupil) is arranged so as to be located at the focal point r2. Further, the first mirror 50 and the second mirror 60 are arranged so that the first turning point formed by the first mirror 50 coincides with the other focal point r1 of the second mirror 60. In the present embodiment, as a result, a second turning point r2 in which the light from the objective optical system 2 toward the fundus Er is swirled is formed at the focal point r2.

The second mirror 60 shown in FIG. 2 is a spheroidal mirror (elliptical mirror). In this case, the light reflected by the mirror surface of the spheroidal mirror via the focal point r1 always passes through the focal point r2. As a result, the light emitted to the eye E to be inspected arranged at the focal point r2 is less likely to be eclipsed in the pupil. In addition, as eclipse is suppressed, fundus photography at a wide angle of view becomes possible.

A curved mirror other than the spheroidal mirror may be applied as the second mirror 60. The curved mirror may be, for example, an aspherical mirror having a mirror surface of a quadric surface like a spheroid mirror (specific examples are a parabolic mirror, a pair of bilateral mirrors, and the like). Further, it may be an aspherical mirror having a shape other than this. Further, although the second mirror 60 in the present embodiment is one mirror, it may be replaced with a combination of a plurality of mirrors. The shape and size of the second mirror 60 are appropriately set according to the angle of view to be photographed. For example, in the present embodiment, it may be formed in a shape and size capable of photographing at a full angle of about 120 °.

With such a mirror configuration, the objective optical system 2 of the present embodiment reduces the swing angle of the light incident on the first mirror 50 via the optical scanners 15 and 22 with respect to the swing angle at the second turning point r2. ..

Here, in the present embodiment, one or both of the first mirror 50 and the second mirror 60 widens the shooting range so that the desired angle of view is obtained. As in the example of FIG. 2, at least the first mirror 50 makes the swing angle of the light from the first turning point r1 toward the second mirror 60 the light incident on the first mirror 50 via the optical scanners 15 and 22. The angle of view may be widened by increasing the swing angle (more preferably, the swing angle of light when incident on the objective optical system 2). The shape and arrangement of such a second mirror 60 can be obtained, for example, by simulation by a ray tracing method or the like.

By the way, suppose that there is no first mirror 50, and optical scanners 15 and 27 of one of the SLO optical system 10 and the OCT optical system 20 are arranged at one focal point r1 of the second mirror 60, and from the optical scanner, If the configuration is such that the light is directly guided to the second mirror 60, the following problems occur. That is, it is difficult to secure a sufficient space between the optical scanner and the second mirror 60. Further, in order to scan light over a wide range on the fundus, it is necessary to increase the swing angle of the optical scanner. In this case, the optical path coupling member 40 is provided with respect to the space between the optical scanner and the second mirror 60. Proper placement becomes even more difficult. Further, some optical path coupling members 40 have an incident angle dependence. For example, the dichroic mirror, which is an example of the optical path coupling member 40, may not be able to properly transmit or reflect light incident at an incident angle having a large error from the design value. Therefore, even if an optical path coupling member such as a dichroic mirror can be arranged between the second mirror 60 and the optical scanner arranged at the position of the focal point r1, in this case, a part of the fundus image. Image quality deteriorates at the angle of view (wide-angle side). For this reason, it becomes substantially difficult to photograph a wide area of the fundus in one or both of the SLO optical system and the OCT optical system.

On the other hand, in the present embodiment, the first mirror 50 is sandwiched between the optical scanners 15 and 27 and the second mirror 60. Then, as a result of the provision of the first mirror 50, the objective optical system 2 has a large swing angle with respect to the swing angle of the light when it is incident on the objective optical system 2 from the scanning optical system 1, and the first turning point r1 Orbit the light in. In other words, the swing angle of the light incident on the first mirror 50 via the optical scanners 15 and 22 can be made smaller than the swing angle at the first turning point r1. In other words, at a position closer to the light source than the second mirror 50, a region where the swing angle of the light is smaller than the swing angle of the light incident on the second mirror 50 can be formed. As a result, it is possible to easily secure a space for arranging the optical path coupling member 40 in a region where the swing angle of the light is smaller than the swing angle of the light incident on the second mirror 50. Further, by arranging the optical coupling member 40 in this region, the problem of the incident angle dependence of the optical path coupling member 40 can be alleviated. For example, as shown in FIG. 1, an optical path coupling member is between the optical scanner 15 and the first mirror 50 of the SLO optical system 10 and between the optical scanner 27 and the first mirror 50 of the OCT optical system 20. By arranging 40, the optical path of the SLO optical system 10 and the optical path of the OCT optical system 20 can be well coupled. As a result, each of the front image and the tomographic image can be obtained satisfactorily.

As shown in FIG. 1, each of the SLO optical system 10 and the OCT optical system 20 may be telecentric on the object side. In this case, since the angle of incidence on the optical path coupling member 40 is constant regardless of the scanning position, the light amount loss due to the optical path coupling can be satisfactorily suppressed, and a good image of the fundus can be obtained.

Further, as shown in FIG. 2, when a spheroidal mirror is used as the second mirror 60, the second mirror 60 causes asymmetric curvature of field (for example, trapezoidal distortion). It is considered that such field distortion may occur even when a shape other than the spheroidal mirror is adopted for the second mirror 60.

The curvature of field caused by the second mirror 60 may be corrected by the first mirror 50. For example, the curvature of field may be corrected by arranging the first mirror 50 at an angle with respect to the second mirror 60. The inclination referred to here is, for example, the first light ray passing through the center of the optical path between the first mirror 50 and the second mirror 60 (mainly a light ray passing through the eye axis of the eye E to be inspected). It means that the mirror 50 is arranged with its axis (for example, the axis of symmetry in the quadratic curve forming the mirror surface of the aspherical mirror) tilted. It is desirable that the amount of inclination is at least such that the asymmetric component of curvature of field is canceled out. That is, an inclination amount may be adopted so that the remaining curvature of field is axisymmetric.

Further, in the example of FIG. 2, as a result of using a spheroid mirror for the second mirror 60, the image plane of the intermediate image such as the intermediate image Ic2 due to the fundus reflected light is tilted obliquely with respect to the optical axis of the optical system. Can be considered. It is considered that such an inclination of the image plane may occur even when a shape other than the spheroidal mirror is adopted for the second mirror 60.

On the other hand, even if the photographing apparatus 100 of the present embodiment is provided with an optical member that corrects the inclination of the image plane caused by the reflection of the fundus reflected light by the first mirror 50 and the second mirror 60. Good.

For example, the optical member that corrects the inclination of the image plane includes a light projecting path until the light from the light sources 11 and 21 is guided to the eye E to be inspected and a light projectile until the reflected light from the fundus is guided to the detectors 18 and 31. It may be arranged in a common optical path with the light receiving optical path. Further, they may be arranged in independent optical paths in each of the light projecting path and the light receiving path.

As a specific example when arranged in the common optical path, correction mirror systems 71 and 72 for correcting the inclination of the image plane in the fundus reflected light may be provided in the objective optical system 2 as an optical member. The correction mirror systems 71 and 72 further tilt the image plane so as to cancel the tilt of the image plane caused by the first mirror 50 and the second mirror 60. As a result, as shown in FIG. 2, in the intermediate image of the fundus reflected light formed through the correction mirror systems 71 and 72 (for example, the intermediate image Ic1 in FIG. 2), the inclination of the image plane is reduced.

As another specific example, the inclination of the image plane may be corrected by arranging a lens tilted with respect to the optical axis in the common optical path. For example, in the example of FIG. 1, the scan lenses 16 and 29 may be tilted.

Further, when the optical member is arranged in each independent optical path of the light projecting optical path and the light receiving optical path, at least the detector 18 of the SLO optical system 10 may be used as one of the optical members. For example, when the SLO optical system 10 is a line scan SLO optical system, a line sensor or an area sensor is used as the detector 18. In this case, the tilt of the image plane can be corrected by tilting the detector 18 with respect to the optical axis of the light receiving optical system 10a. It is desirable that the amount of inclination of the detector 18 is adjusted so as to have a relationship between the fundus Er and the objective optical system 2 and the Scheimpflug. In addition, an optical member such as a lens that is inclined with respect to the optical axis may be provided in the independent optical path of the projection optical system 10a in the SLO optical system 10.

When the SLO optical system 10 is a point scan SLO optical system, an optical member (for example, a lens arranged at an angle) is provided on the light receiving optical path from the detector to the eye E to be inspected separately from the detector. It is desirable to provide a correction mirror system, etc.). As a result, by suppressing the inclination of the image plane, it is possible to prevent the confocal position of the fundus Er from moving in response to the change in the scanning position by the optical scanner 15. As a result, a stationary fundus conjugate point can be formed between the optical member and the detector 18. Therefore, the aperture for removing harmful light can be arranged at a stationary confocal position, and a good front image can be obtained.

<Example>
The photographing apparatus 100 in the first embodiment will be described with reference to FIG. The photographing apparatus 100 in the first embodiment includes the scanning optical system 1 shown in FIG. 1 and the objective optical system 2 shown in FIG. The scanning optical system 1 includes an SLO optical system 10, an OCT optical system 20, and a dichroic mirror 40 (optical path coupling member in the first embodiment).

<SLO optical system>
First, the SLO optical system 10 will be described. The SLO optical system 10 mainly includes an optical scanner 15 that scans light (illumination light) emitted from a light source two-dimensionally on the fundus, and a detector 18 that passes through the cofocal point of the fundus Er (illumination). It has a light receiving optical system 10a that allows a detector to receive light reflected from the fundus of the eye (of light). Further, in the first embodiment, the SLO optical system 10 is a line scan type, and a line sensor is used for the detector 18. In this case, the SLO optical system 10 includes an optical scanner 15, a detector 18, a light source 11, a collimating lens 12, a cylindrical lens 13, a perforated mirror 14, a scan lens 16, and a condenser lens. 17 and may have. Of these, the optical scanner 15, the scanning lens 16, the condenser lens 17, and the line sensor (detector) 18 constitute the light receiving optical system 10a of the SLO optical system 10 in the first embodiment.

In the first embodiment, the light source 11 emits light having a wavelength in the infrared region (for example, laser light). As the light source 11, for example, an LED light source, an SLD light source, or the like may be used. The light from the light source 11 is collimated by the collimating lens 12 and then condensed by the cylindrical lens 13. After that, it passes through the opening of the perforated mirror 14 and is guided to the optical scanner 15. The light emitted from the light source 11 is not necessarily limited to infrared light. For example, it may be white light, or it may be synthetic light in which light such as two or more colors of light (for example, red, blue, and green) is combined.

In the first embodiment, a galvanometer mirror may be used for the optical scanner 15. However, the present invention is not limited to this, and it may be replaced with any other optical scanner (for example, resonant mirror, polygon mirror, etc.) that operates the reflection mirror, an acoustic optical element, or the like. The optical scanner 15 is arranged at a position conjugate with the pupil of the eye E to be inspected.

The light that has passed through the optical scanner 15 is made into a ray parallel to the optical axis L1 of the scanning optical system 1 (that is, a telecentric ray) by the scan lens 16. That is, in the first embodiment, the scan lens 16 is arranged so that its focus coincides with the optical scanner 15 (the turning point r3 of the optical scanner 15). As a result, the SLO optical system 10 in the first embodiment becomes an object-side telecentric lens. The light that has passed through the scan lens 16 further passes through the dichroic mirror 40 and is incident on the objective optical system 2. In the first embodiment, the dichroic mirror 40 has a spectral characteristic of transmitting light from the SLO optical system 10 and reflecting light from the OCT optical system 20. The object-side telecentric means a state of being telecentric to the eye E side when viewed from the light sources 11 and 22 sides.

The light from the SLO optical system 10 is guided to the fundus Er by the objective optical system 2, and is scattered and reflected by the fundus Er. As a result, it is emitted from the pupil as the fundus reflected light and follows the optical path opposite to that at the time of projection. Then, the fundus reflected light is emitted from the objective optical system 2 toward the scanning optical system 1, passes through the dichroic mirror 40, and is incident on the light receiving optical system 10a of the SLO optical system 10. In the light receiving optical system 10a, the fundus reflected light passes through the scan lens 16 and is reflected by the optical scanner 15 toward the perforated mirror 14. After that, the fundus reflected light reflected by the perforated mirror 14 is collected by the condenser lens 17 and received by the detector 18. In the present embodiment, a frontal image of the fundus is formed based on the signal output from the detector 18 based on the optical scanning of one frame by the optical scanner 15.

<OCT optical system>
Next, the OCT optical system 20 will be described. The OCT optical system 20 may include, for example, a light source 21, an optical dividing unit (coupler in the example of FIG. 1) 23, an optical scanner 27, and a detector 31. The OCT optical system 20 may further include a scan lens 29 and a reference optical system 25.

As such an OCT optical system 20, a Fourier domain method such as an SS-OCT (Swept Source-OCT) method or an SD-OCT (Spectral domain-OCT) method may be used.
Here, as an example, the SS-OCT (Swept Source-OCT) method will be described.

The light source 21 is a tunable light source (wavelength scanning light source) that changes the emission wavelength at high speed in time. The light source 21 changes the wavelength of the emitted light. The detector 31 may be, for example, a balanced detector including a light receiving element.

The OCT optical system 20 divides the light emitted from the light source 21 into measurement light and reference light by a coupler (splitter) 23.

The OCT optical system 20 guides the measurement light to the objective optical system 2 via the optical scanner 27. Further, the reference light is guided to the reference optical system 25. The optical scanner 27 scans the measurement light in the XY direction (transverse direction) on the fundus Er. The optical scanner 27 is, for example, two galvano mirrors, and the reflection angle thereof may be arbitrarily adjusted by a drive mechanism (not shown). Further, instead of the galvano mirror, another optical scanner (for example, a resonant mirror, a polygon mirror, etc.) that operates a reflection mirror, an acoustic optical element, or the like may be used.

The light passing through the optical scanner 27 is made into a ray parallel to the optical axis of the scanning optical system 1 (that is, a telecentric ray) by the scan lens 29. That is, in the first embodiment, the scan lens 29 is arranged so that its focus coincides with the optical scanner 27 (for example, the intermediate point r4 between the optical scanner for X scanning and the optical scanner for Y scanning). There is. As a result, the OCT optical system 20 in this embodiment becomes an object-side telecentric lens. The light that has passed through the scan lens 29 is reflected by the dichroic mirror 40 and is incident on the objective optical system 2.

Similar to the light from the SLO optical system 10, the light from the OCT optical system 20 is scattered and reflected by the fundus by being guided to the fundus Er by the objective optical system 2. As a result, the fundus reflected light of the measurement light is emitted toward the scanning optical system 1 by tracing the objective optical system 2 in the direction opposite to that at the time of projection. As a result, the fundus reflected light of the measurement light is reflected by the dichroic mirror 40 and incident on the detection optical system 20a of the OCT optical system 20 (the light receiving optical system of the OCT optical system 20). That is, the fundus reflected light passes through the scan lens 29, passes through the optical scanner 27, and is incident on the coupler (splitter) 23. After that, the reflected light of the measurement light is combined with the reference light by the optical coupling portion (coupler) 23 and interferes with the reference light.

The reference optical system 25 generates a reference light that is combined with the reflected light acquired by the reflection of the measurement light on the fundus Er. The reference optical system 25 may be, for example, a Michaelson type or a Machzenda type. In FIG. 1, the reference optical system 25 is formed by, for example, a reflective optical system (for example, a reference mirror), and guides the reference light to the detector 31 by reflecting the light from the coupler 23 by the reflective optical system. As another example, the reference optical system 25 may be formed by a transmission optical system (for example, an optical fiber) and may be guided to the detection optical system 31 by transmitting the light from the coupler 23 without returning it.

The photographing apparatus 100 moves at least a part of the optical members arranged in the OCT optical system 20 in the optical axis direction in order to adjust the optical path length difference between the measurement light and the reference light. For example, the reference optical system 25 has a configuration in which an optical path length difference between the measurement light and the reference light is adjusted by moving an optical member (for example, a reference mirror (not shown)) in the reference optical path. For example, the reference mirror is moved in the optical axis direction by driving the drive mechanism 25a. The configuration for changing the optical path length difference may be arranged in the optical path of the measurement light. That is, the optical path length difference between the measurement light and the reference light may be adjusted by changing the optical path length of the measurement light.

The interference signal light, which is a combination of the measurement light and the reference light, is received by the detector 31. The detector 31 detects the interference signal light. Here, when the emission wavelength is changed by the light source 21, the interference signal light corresponding to this is received by the detector 31, and as a result, is received by the detector 31 as spectral interference signal light. A depth profile (also referred to as A scan or OCT data) at one point on the fundus is formed based on the spectral interference signal output from the detector 31. The depth profile is the reflection intensity distribution of the measured light in the depth direction of the fundus. By arranging the depth profiles (OCT data), two-dimensional OCT data (for example, a tomographic image of the fundus and OCT angiography) is formed.

<Objective optical system>
Next, the objective optical system 2 according to the first embodiment will be described with reference to FIG. In the example of FIG. 2, the second mirror 60 is a single spheroidal mirror. The second mirror 60 has two focal points r1 and r2. The eye E to be inspected is arranged at one of the focal points r2.

In the first embodiment, the first mirror 50 is a parabolic mirror. In the first embodiment, the focal point of the first mirror 50, which is a parabolic mirror, and one of the two focal points (focus r1) of the second mirror 60, which is a rotating elliptical mirror, coincide with each other. The first mirror 50 and the second mirror 60 are arranged. Further, the remaining one (focus r2) of the two focal points of the second mirror 60 is arranged in the anterior segment of the eye E to be inspected. In this case, the convex surface of the first mirror 50 and the concave surface of the second mirror 60 are used as the respective reflection surfaces. Here, the parabolic mirror apparently converts the light incident parallel to the axis of symmetry Z2 into the light emitted from the focal point r1. Further, the first mirror 50 further focuses the light emitted from one focal point r1 on the other focal point r2. Therefore, in the first embodiment, the light from the object-side telecentric SLO optical system 10 and the OCT optical system 20 is incident on the first mirror 50 as parallel light with respect to the axis of symmetry of the first mirror 50, thereby causing the SLO. The light from the optical system 10 and the light from the OCT optical system 20 can be swirled around the focal point r2 located in the anterior segment of the eye E to be inspected. In this way, the first mirror 50 and the second objective mirror 60 in the objective optical system 2 are provided in the above-mentioned shape and arrangement, so that the light incident on the first mirror 50 via the optical scanners 15 and 22 is shaken. It is possible to scan a wide area of the fundus while suppressing the horns.

Although the case where the first mirror 50 is a parabolic mirror has been described, the first mirror 50 is one of specific examples of an aspherical mirror for widening the shooting image angle, and is a parabolic surface. An aspherical mirror other than the mirror may be applied as the first mirror 50.

Further, in the first embodiment, in addition to the first mirror 50 and the second mirror 60, correction mirror systems 71 and 72 are provided in the objective optical system 2. In the first embodiment, the correction mirror systems 71 and 72 are composed of a parabolic mirror 71 and a plane mirror 72. The correction mirror systems 71 and 72 correct the inclination of the image plane caused by the reflection of the fundus reflected light by the parabolic mirror which is the first mirror 50 and the rotating elliptical mirror which is the second mirror 60. Further, in the first embodiment, the light from the object-side telecentric SLO optical system 10 and the OCT optical system 20 is incident on the first Mira-50 as light parallel to the axis of symmetry Z2.

In the first embodiment, the parabolic mirror 71 has a concave surface formed symmetrically with the axis of symmetry z1 in between. The light from the scanning optical system 1 is incident parallel to the axis of symmetry z1. Further, the plane mirror 72 is arranged so as to face the parabolic mirror 71 at the focal position r5 of the parabolic mirror 71. When light from the scanning optical system 1 is incident on such correction mirror systems 71 and 72, the order is parabolic mirror 71 → plane mirror 72 (that is, focal point r5 of the parabolic mirror) → parabolic mirror 71. Is reflected and emitted parallel to the axis of symmetry z1. Therefore, the luminous flux becomes telecentric on both sides of the correction mirror systems 71 and 72. Further, the image plane is tilted by the reflection of the correction mirror systems 71 and 72 (see the intermediate image Ic2 in FIG. 2). This inclination is performed in a direction that cancels the inclination of the image plane caused by the first mirror 50 and the second mirror 60. As shown in FIG. 2, when the inclination generated by the first mirror 50 and the second mirror 60 is non-linear, it is desirable that the correction mirror systems 71 and 72 cancel at least the non-linear component of this inclination. ..

The first mirror 50 in the first embodiment is a convex mirror whose convex surface is directed with respect to the parabolic mirror 71 and the second mirror 60. That is, the first mirror 50 has a negative power. The first mirror 50 is arranged eccentrically (off the axis) with respect to the parabolic mirror 71. That is, the axis of symmetry z2, which is the axis of symmetry of the mirror surface of the first mirror 50 (that is, the target axis of the parabolic surface), is parallel to the axis of symmetry z1 of the parabolic mirror 71 at intervals. Therefore, the first mirror 50 is irradiated with a light ray parallel to the axis of symmetry z2 from the parabolic mirror 71. Further, the first mirror 50 is arranged so that the focus of the first mirror 50 is aligned with one of the two focal points r1 and r2 of the second mirror 60, which is a rotating elliptical mirror. Therefore, when light is irradiated from the parabolic mirror 71 to a certain position of the first mirror 50, the light is reflected on a straight line connecting the irradiation position and the focal point r1. That is, the light directed from the first mirror 50 to the second mirror 60 rotates around the focal point r1 of the spheroidal mirror, which is the second mirror, as the optical scanner 15 (or the optical scanner 27) is driven. In other words, the first mirror 50 forms a turning point of light at the focal point r1 via the optical scanner 15 (or the optical scanner 27) toward the second mirror 60. In the first embodiment, the light is reflected by the mirror surface of the first mirror 50, so that the swing angle of the light from the first turning point r1 to the second mirror is incident on the first mirror 50 from the scanning optical system 1. It is increased with respect to the swing angle of light. Therefore, in the first embodiment, the swing angle of the light incident on the first mirror 50 is suppressed more than the swing angle of the light incident on the second mirror 60. As an example, as shown in FIG. 1, telecentric light can be incident. In this case, it is assumed that the swing angle = 0.

Further, due to the general characteristics of the spheroid mirror, which is the second mirror 60, the light that has passed through the focal point r1 and is reflected by the mirror surface of the spheroidal mirror is guided to the other focal point r2. Therefore, a turning point (second turning point) of the light reflected by the second mirror 60 is formed at the other focal point r2 (that is, the position of the anterior eye portion of the eye E to be inspected). The swing angle of light at this turning point (focus r2) is determined by the swing angle at focus r1 and the shape of the mirror surface on the second mirror 60. The second mirror 60 may have a shape in which the swing angle at the focal point r2 is made larger than the swing angle at the focal point r1. However, it is not necessarily limited to this.

As described above, in the first embodiment, light is telecentically (swing angle = 0) incident on the objective optical system 2 (more specifically, the parabolic mirror 71) from the scanning optical system 1 to the fundus. It is possible to shoot a wide range of Er. In the first embodiment, the optical coupling member 40 (dichroic mirror 40) for coupling the optical path between the SLO optical system 10 and the OCT optical system 20 becomes telecentric for each of the SLO optical system 10 and the OCT optical system 20. Since it is arranged at the location where the image is located, a wide angle of view front image and a tomographic image can be obtained well.

Here, since the second mirror 60 is a spheroidal mirror, it causes asymmetric curvature of field (for example, trapezoidal distortion) in the fundus reflected light. On the other hand, in this embodiment, the curvature of field is suppressed by arranging the first mirror 50 at an angle with respect to the second mirror 60. That is, the first mirror 50 is arranged at an angle with respect to a light ray passing through the center of the optical path between the first mirror 50 and the second mirror 60. The amount of correction for curvature of field changes according to the amount of inclination of the first mirror 50. The amount of inclination of the first mirror 50 may be set so that the remaining curvature of field is axisymmetric, for example.

<Control system>
Next, the control system of the photographing apparatus 100 will be described with reference to FIG. The control unit 70 is a processor (for example, a CPU) that controls the entire device of the photographing device 100.

In the first embodiment, the memory 72, the monitor 75, etc. are electrically connected to the control unit 70. Further, light sources 11, 21, optical scanners 15, 27, detectors 18, 31, drive mechanism 25a, and the like are electrically connected to the control unit 70.

The memory 72 stores various control programs and fixed data. Further, the memory 72 may store an image, temporary data, or the like taken by the photographing device 100.

In the present embodiment, the control unit 70 also serves as an image processing unit. For example, the received signals from the detector 18 and the detector 31 are input to the control unit 70, respectively. The control unit 70 forms a frontal image of the fundus Er based on the signal from the detector 18. Further, the control unit 70 forms a tomographic image of the fundus Er based on the signal from the detector 31. At this time, the control unit 70 drives the light from the light source 11 and the light from the light source 21 at the same time and independently of the optical scanner 15 to obtain a front image and a tomographic image. May be acquired in parallel. The front image and the tomographic image obtained at the same time may be simultaneously displayed as a moving image on the monitor 75. In the first embodiment, since the optical scanner 15 of the SLO optical system 10 and the optical scanner 27 of the OCT optical system 20 are independently provided, the control unit 70 makes the front image and the tomographic image different from each other. It may be acquired at the frame rate.

<Second Example>
Next, a second embodiment will be described with reference to FIG. In the second embodiment, the same configurations as those in the first embodiment are designated by the same reference numerals as those in the first embodiment, and detailed description thereof will be omitted.

In the second embodiment, a part of the scanning optical system 1 and the objective optical system 2 is different from the first embodiment. For example, in the first embodiment, each of the SLO optical system 10 and the OCT optical system 20 was telecentric on the object side, but in the second embodiment, the scanning optical system 1 (more specifically, the SLO optical system 10). The light incident on the objective optical system 2 from the OCT optical system 20) is swirled around a swirl point at a finite distance from the objective optical system 2. In the second embodiment, for convenience of explanation, the light from the SLO optical system 10 when incident on the objective optical system 2 is swirled around the turning point r3, and the OCT optical when incident on the objective optical system 2 It is assumed that the light from the system 20 is swirled around the swirl point r4.

The objective optical system 2 of the second embodiment has a parabolic mirror 171 between the first mirror 50 and the optical scanners 15 and 27. The parabolic mirror 171 is a concave mirror whose focal point is arranged so as to coincide with the turning points r3 and r4. Therefore, the luminous flux becomes telecentric on the object side of the parabolic mirror 171. Further, in the second embodiment, the target axis of the mirror surface in the parabolic mirror 171 (that is, the axis of symmetry of the parabolic surface, not shown) is parallel to the axis of symmetry z2 of the mirror surface in the first mirror 50. Have been placed. Therefore, as in the first embodiment, the first mirror 50 is irradiated with light rays parallel to the axis of symmetry z2 from the optical scanners 15 and 27 (that is, the parabolic mirror 171). As a result, the light from the first mirror 50 toward the second mirror 60 is swirled around the first swivel point r1 at the position where the focal point of the first mirror 50 and the focal point of the second mirror 60 overlap. Further, the light is reflected by the second mirror 60, so that the light is swirled around the other focal point r2 of the spheroidal mirror as a swirling point. In this way, also in the second embodiment, the fundus Er is suppressed while suppressing the swing angle of the light incident on the objective optical system 2 (more specifically, the parabolic mirror 171) from the scanning optical system 1. It is possible to scan light well in a wide range. As a result, it is possible to prevent the image quality of the fundus image from being partially deteriorated due to the incident angle dependence of the optical coupling member 40 (dichroic mirror 40).

When the fundus image is taken at the desired angle of view, the longer the focal length of the parabolic mirror 171 is, the more the swing angle of light in the optical scanners 15 and 27 can be suppressed. For this reason, it is preferable that the parabolic mirror 171 having a longer focal length is applied within the range of the allowable device size. It is considered that this makes it possible to more effectively reduce the problem of the incident angle dependence of the optical path coupling member 40.

According to the inventor of the present invention, when the optical system of the first embodiment and the optical system of the second embodiment are designed under certain conditions, the second embodiment has higher imaging performance. It was confirmed that it plays.

By the way, the parabolic mirror 171 provided instead of the correction optical systems 71 and 72 of the first embodiment does not correct the inclination of the image plane. On the other hand, in the second embodiment, at least, in order to suppress the inclination of the image plane in the SLO optical system 10, at least the detector 18 is provided so as to be inclined with respect to the optical axis of the light receiving optical system 10a. It is also good. At the same time, either the lens 12 or the lens 13 in the SLO optical system 10 may be tilted with respect to the optical axis. In such a second embodiment, the amount of inclination of the detector 18 is adjusted so as to have a relationship between the fundus Er and the objective optical system 2 and Scheimpflug. As a result, it is possible to prevent the image quality from being deteriorated due to the inclination of the image plane (that is, the focus differs depending on the scanning position).

<Third Example>
Next, a third embodiment will be described with reference to FIG. In the third embodiment, the same configurations as those in the first embodiment are designated by the same reference numerals as those in the first embodiment, and detailed description thereof will be omitted. In the third embodiment, the shape of the first mirror 50 is mainly different from that of the first embodiment and the second embodiment. Further, in the third embodiment, the mirror system is not included between the first mirror 50 and the scanning optical system 1. In the third embodiment, a part of the scanning optical system 1 and the objective optical system 2 is different from the first embodiment. For example, in the first embodiment, each of the SLO optical system 10 and the OCT optical system 20 was telecentric on the object side, but in the third embodiment, as in the second embodiment, the scanning optical system 1 (more detailed). The light incident on the objective optical system 2 from the SLO optical system 10 and the OCT optical system 20) is swirled around a swirl point at a finite distance from the objective optical system 2.

In the third embodiment, the first mirror 50 is one hyperboloid mirror (one of a pair of hyperboloids). The hyperboloid mirror is an aspherical mirror that contributes to widening the angle in the third embodiment. The second mirror 60 may be a spheroidal mirror as in the first embodiment. The bi-curved mirror, which is the first mirror 50, is arranged so that the focal point on the virtual image side (the focal point on the convex surface side) coincides with the turning points r3 and r4. Further, the first mirror 50 is arranged so that the focal point on the real image side (the focal point on the concave surface side) coincides with one focal point of the second mirror 60. That is, the first mirror 50 is irradiated with light emitted from the focal point on the virtual image side (the hyperboloid side paired with the first mirror 50). As a result, due to the general characteristics of the bi-curved mirror, the reflected light reflected by the first mirror 50 is focused on the real image side of the first mirror 50 as the optical scanner 15 (or the optical scanner 27) is driven. It turns around r1. Here, since the focal point r1 is also the focal point of the second mirror 60 which is a rotating elliptical mirror, the turning point of the light reflected by the first mirror 50 is the focal point r1 of the rotating elliptical mirror due to the arrangement of the first mirror 50. Is formed in. In the third embodiment, the light is reflected by the mirror surface of the first mirror 50, so that the swing angle of the light from the first turning point r1 to the second mirror 60 is incident on the first mirror 50 from the scanning optical system 1. It is increased with respect to the swing angle of the light. Then, the light reflected by the second mirror 60 is swirled with the other focal point r2 of the second mirror 60 as a turning point. In this way, also in the third embodiment, the wide range of the fundus Er is suppressed while suppressing the swing angle of the light incident on the objective optical system 2 (more specifically, the first mirror 50) from the scanning optical system 1. The light can be scanned satisfactorily.

The first mirror 50 in the third embodiment is a hyperboloid mirror (eccentricity> 1), and the closer the eccentricity of the hyperboloid is to 1, that is, the mirror shape is the paraboloid shown in the first embodiment. It approaches the surface shape. Therefore, as the eccentricity of the hyperboloid approaches 1, the focal point on the virtual image side (focus on the convex surface side) becomes farther from the mirror surface and approaches infinity. Therefore, when the fundus image is taken at the desired angle of view, the closer the eccentricity of the first mirror 50 is to 1, the more the light swing angle of the optical scanners 15 and 27 can be suppressed. Therefore, it is preferable that a hyperboloid mirror having an eccentricity closer to 1 is applied to the first mirror 50 within an allowable device size range. It is considered that this makes it possible to more effectively reduce the problem of the incident angle dependence of the optical path coupling member 40.

As shown in FIG. 5, the first mirror 50 may be arranged at an angle with respect to the second mirror 60. In order to correct the inclination of the image plane that occurs in this case, for example, the detector 18 of the SLO optical system 10 or the like may be arranged at an angle with respect to the optical axis.

<Operation of the device when acquiring a tomographic image>
The objective optical system 2 of each of the above embodiments is in front of the eye E to be inspected via a mirror system (for example, the first mirror 50 and the second mirror 60) arranged between the eye E to be inspected and the optical scanner 27. This is an objective mirror system that forms a turning point (turning point r2 in each of the above embodiments) that is swiveled by the operation of the optical scanner 27 at the eye portion (for example, the position of the pupil). In the objective optical system 2, for example, in each of the above embodiments, the second mirror 60 immediately before the eye E to be inspected is a spheroidal mirror, and one of the two focal points r1 and r2 of the spheroidal mirror is set. The turning point r2 is formed. Of the two focal points in the spheroidal mirror, the light incident from one of the two focal points toward the mirror surface and guided to the other focal point always has a constant optical path length between the two focal points. However, in each of the above embodiments, the measurement light from the optical scanner 27 to the second turning point r2 is measured by arranging a mirror such as the first mirror 50 between the optical scanner 27 and the second mirror 60. The distance may vary depending on the scanning position of the optical scanner 27.

Further, in each of the above embodiments, the optical path length of the measurement light from the second turning point r2 (pupil position) to the surface of the fundus Er is also different for each scanning position. That is, due to the curvature of the fundus, the distance of the measured light from the second turning point r2 to the fundus Er may differ depending on the scanning position of the optical scanner 27.

As described above, it is conceivable that the distance of the measured light from the optical scanner 27 to the eye E to be inspected differs at each scanning position of the optical scanner 27. That is, it is conceivable that the optical path length difference between the measurement light and the reference light changes depending on the distance of the measurement light from the optical scanner 27 to the eye E to be inspected at each scanning position of the optical scanner 27.

In this state, when the depth profile (OCT data) is obtained based on the signal from the detector 31, the depth position of the region where the depth profile (OCT data) is acquired in the eye E to be examined is the depth position of the optical scanner 27. It is conceivable that it will be different for each scanning position. Further, depending on the scanning position, it is conceivable that the range in which the sensitivity of the detector 31 is high and the range in which the measurement light and the reference light interfere with each other are relatively largely deviated due to the large difference in the optical path length.

On the other hand, the control unit 70 corrects the change in the optical path length difference between the measurement light and the reference light due to the distance of the measurement light from the optical scanner 27 to the eye E to be inspected at each scanning position of the optical scanner 27.

Here, the change in the optical path length difference between the measurement light and the reference light may be corrected on the data (by processing the OCT data). For example, the control unit 30 may correct the position information in the depth direction of the OCT data when the control unit 30 acquires the OCT data based on the signal from the detector 31.

Further, when the control unit 30 arranges a plurality of OCT data to form the two-dimensional OCT data, the control unit 30 may correct the relative depth position between the OCT data of each scanning position.

As a result of performing such processing, OCT data (or two-dimensional OCT data) can be obtained satisfactorily.

Further, the change in the optical path length difference between the reference light and the measurement light may be optically corrected. For example, the correction may be performed by driving and controlling the optical path length adjusting mechanism 25a (driving mechanism) according to the scanning position of the optical scanner 27. As described above, the drive mechanism 25a displaces an optical member (for example, a mirror) arranged on the optical path of the reference light (or the optical path of the measurement light), thereby causing an optical path length difference between the measurement light and the reference light. May be adjusted. For example, in this embodiment, the optical path length of the reference light is changed by the drive mechanism 25a in accordance with the change in the optical path length of the measurement light accompanying the operation of the optical scanner 27. As a result, a signal based on the interference between the measurement light and the reference light can be easily detected in a range where the sensitivity of the detector 31 is high, and OCT data (or two-dimensional OCT data) can be obtained satisfactorily. In this case, the range in which the optical path length difference changes is suppressed so that the signal based on the interference between the measurement light and the reference light is detected in the range where the sensitivity of the detector 31 is relatively high, regardless of the scanning position. If possible, the drive mechanism 25a does not necessarily have to be driven and controlled so that the optical path length difference between the measurement light and the reference light is constant (for example, zero) at each scanning position.

Here, the control unit 70 corrects the change in the optical path length difference between the measurement light and the reference light in consideration of at least the change in the distance (optical path length) of the measurement light from the optical scanner 27 to the second turning point r2. .. Further, the control unit 70 further considers the change in the optical path length of the measurement light at each scanning position due to the curvature of the fundus (that is, the change in the optical path length of the measurement light from the second turning point r2 to the fundus Er). You may make a correction. Here, the correspondence between the optical path length of the measured light from the optical scanner 27 to the second turning point r2 and each scanning position of the optical scanner 27 is determined by the design of the optical system. In addition, the correspondence between the optical path length of the measured light from the second turning point to the fundus Er and each scanning position of the optical scanner 27 is also approximately determined by the design of the optical system (mainly the swing angle at the second turning point). It is decided.

Therefore, for example, the correction amount for correcting the change in the optical path length difference (for example, the amount of change in the optical path length or the amount of correction of the position information in the depth direction in the OCT data) corresponds to each scanning position of the optical scanner 27. The attached correction table may be prepared in advance in the memory 72. Then, the control unit 70 may perform correction processing of the change in the optical path length difference by using this correction table. The correction amount in such a table is a value considering at least the change in the optical path length of the measured light from the optical scanner 27 to the second turning point r2. Further, the value may be a value in consideration of the change in the optical path length from the second turning point r2 to the fundus E2. The correspondence relationship between the optical path length difference and the correction amount (in other words, the correspondence relationship between the scanning position and the correction amount) may be obtained in advance by, for example, simulation and calibration.

In the above embodiment, the optical scanner 27 includes two optical scanners. That is, the first optical scanner (for example, X galvano scanner) that performs the main scanning of the measurement light and the second optical scanner (for example) that performs the sub-scanning of the measurement light in the direction intersecting the direction of the main scanning are include. When the main scan is performed in the depth direction of the paper surface of each figure and the sub scan is performed in the direction intersecting the depth direction of the paper surface, the change in the optical path length in the measurement light (more) depends only on the position of the sub scan. Specifically, it is possible to employ an objective optical system 2 that causes a change in the optical path length from the optical scanner 27 to the second turning point r2). For example, as in the present embodiment, the objective optical system 2 as described above can be realized by using a concave mirror and a convex mirror formed from a rotating curved surface such as a rotating elliptical mirror and a rotating parabolic mirror.

With respect to such an objective optical system 2, the control unit 30 may acquire two-dimensional OCT data in a plurality of scan lines by raster-scanning the measurement light. That is, by driving and controlling the optical scanner 27, the control unit 30 acquires a plurality of two-dimensional OCT data acquired by the main scan at scan lines having different directions of the sub scan. Then, the drive mechanism 25a may be driven and controlled according to the scanning position of the second scanner. That is, the change in the optical path length difference between the reference light and the measurement light may be corrected by driving the drive mechanism 2 according to the scanning position of the second scanner.

In this case, the optical path length difference between the measurement light and the reference light may change with the sub-scan, but the speed of the sub-scan is slower than that of the main scan. Therefore, the time change of the optical path length difference can be suppressed. Therefore, the drive mechanism 25a can be driven so that the change in the optical path length difference between the reference light and the measurement light is corrected more reliably. As a result, a plurality of two-dimensional OCT data can be obtained satisfactorily.

Although the above description has been given based on the embodiment, the present disclosure is not limited to the above embodiment, and various modifications may be made.

For example, in the first to third embodiments, the second mirror 60 in the objective optical system 2 is a spheroid mirror, and the first mirror 50 used in combination with this is a parabolic mirror or a hyperboloid mirror. It was. In other words, in the first to third embodiments, the first mirror 50 is a curved surface formed by a locus of a quadratic curve having an eccentricity ≥ 1 rotated around an axis of symmetry. However, as described above, the curved surface shapes of the first mirror 50 and the second mirror 60 may be appropriately selected from various quadric surfaces or aspherical surfaces, respectively.

For example, in the above embodiment, the scanning optical system 1 has an optical path coupling portion 40 in which the optical paths of two photographing optical systems (in the above embodiment, the SLO optical system 10 and the OCT optical system 20) each have an optical scanner. The case of being combined by is described. However, the present invention is not necessarily limited to this, and in the scanning optical system 1, the optical paths of the photographing optical system and the irradiation optical system that emits therapeutic or stimulating light may be coupled by the optical path coupling portion 40. .. The photographing optical system referred to here is a detection in which the light from the first light source for photographing is scanned on the fundus by driving the first optical scanner, and the light reflected from the fundus of the first light source is received. It may be equipped with a vessel. In this case, for example, any one of the SLO optical system 10 and the OCT optical system 20 in the above embodiment may be used as the photographing optical system. On the other hand, the light emitted to the eye E to be inspected by the irradiation optical system may be, for example, a therapeutic laser for performing photocoagulation on the fundus. Further, it may be a stimulus light for a visual field test. Of course, the therapeutic or stimulating light is not limited to this. Such an irradiation optical system may have at least a second optical scanner that determines the irradiation position of the light on the fundus by deflecting the light from the second light source that emits therapeutic or stimulating light. Good. Such an irradiation optical system may be replaced with any of the SLO optical system 10 and the OCT optical system 20 in the above embodiment, and the second optical scanner may be replaced with any of the optical scanners 15 and 27 in the above embodiment. And may be arranged.

In the present disclosure, the following fundus photography apparatus is further disclosed as a means for solving various problems that occur when performing wide-angle photography with a line scan SLO.

(First fundus photography device)
A line scan SLO optical system having an optical scanner that scans line-shaped light guided from a light source and a line sensor or area sensor for receiving reflected light from the fundus, and between the optical scanner and the eye to be inspected. An objective optical system arranged in, a curved mirror on which the eye to be inspected is focused, and distortion correction optics that guide the light from the optical scanner to the curved mirror and cancel the image plane distortion caused by the curved mirror. An objective optical system having a system and a fundus imaging device having the system.

In the above embodiment, the curvature of field caused by the second mirror 60 (an example of a “curved mirror”) is a mirror (first mirror 50 and correction mirror) arranged between the second mirror 60 and the optical scanners 15 and 27. It was canceled (in other words, reduced) by the combination with the systems 71 and 72, or the combination of the first mirror 50 and the correction mirror 171). However, the distortion correction optical system does not necessarily have to be formed only by a reflective element such as a mirror. For example, some or all of them may contain a refracting element such as a lens. The refracting element may be any one that reduces curvature of field caused by the "curved mirror". Specifically, the lens may be eccentrically arranged with respect to the optical axis, may be an aspherical lens, or may have other configurations.

(Second fundus photography device)
In the first fundus imaging apparatus, the curved mirror has a first focus and a second focus, the optical scanner is at a conjugate position of the first focus, and the eye is inspected at the second focus, respectively. An elliptical mirror to be arranged, the distortion correction optical system is arranged between the optical scanner and the first focal point, or between the first focal point and the second focal point.

In the second fundus photography apparatus, when the distortion correction optical system is arranged between the optical scanner and the first focal point, the optical scanner may be arranged at the first focal point.

(Third fundus photography device)
In the first or second fundus photography device, the line sensor or area sensor is tilted so as to have a shineproof relationship with the fundus and the objective optical system, or the fundus reflected light passes through the objective optical system. It has an optical member that corrects the inclination of the image plane caused by the above.

(Fourth fundus photography device)
A line scan SLO optical system having an optical scanner that scans line-shaped light guided from a light source and a line sensor or area sensor for receiving reflected light from the fundus, and between the optical scanner and the eye to be inspected. An objective optical system arranged in, which has at least one curved mirror, and reflects light from a light source guided by an optical scanner by the curved mirror to form the light formed at the focal point of the curved mirror. It has an objective optical system that guides the light to the fundus via a turning point, and further, a line sensor or an area sensor is tilted so as to have a shineproof relationship with the fundus and the objective optical system, or the fundus. A fundus imaging apparatus having an optical member that corrects an inclination of an image plane caused by reflection of reflected light by the curved mirror.

(Fifth fundus photography device)
In the fourth fundus photography apparatus, the curved mirror has a first focus and a second focus, the optical scanner is at the conjugate position of the first focus, and the eye to be inspected is at the second focus, respectively. It is an optometry mirror to be placed.

(Sixth fundus photography device)
In the fifth fundus photography apparatus, the objective optical system further has a distortion correction optical system that guides the light from the optical scanner to the curved mirror and cancels the curvature of field caused by the curved mirror.

(7th fundus photography device)
In the sixth fundus photography apparatus, the distortion correction optical system is arranged between the optical scanner and the first focal point, or between the first focal point and the second focal point.

(8th fundus photography device)
In the third or fourth fundus imaging device, the light path of the light reflected from the fundus between the optical scanner and the line sensor or the area sensor in the line scan SLO optical system is on the light path of the light projected from the light source. The optical members are arranged on independent optical paths.

1 Scanning optical system 2 Objective optical system 10 SLO optical system 20 OCT optical system 11 and 21 Light source 15, 27 Optical scanner 18 Detector 40 Optical path coupling member 50 First mirror 60 Second mirror 71, 72 Correction mirror system 100 Eye fundus imaging device r1 1st turning point r2 2nd turning point E Eye to be inspected Er Eye bottom

Claims (9)

A scanning optical system having an optical scanner that changes the traveling direction of the light in order to scan the light from the light source on the fundus of the eye to be inspected.
An image of the fundus, which is arranged between the optical scanner and the eye to be inspected, has an objective optical system for guiding the light from the optical scanner to the fundus, and is based on the fundus reflected light of the light. It is a fundus photography device that forms
The objective optical system is
By reflecting the light from the optical scanner, a first mirror forming a first turning point at which the light is swiveled with the operation of the optical scanner, and
It has a second mirror that forms a second turning point at which the light emitted to the eye to be inspected is swirled by further reflecting the light reflected by the first mirror.
A fundus photography apparatus characterized in that the swing angle of light incident on the first mirror is smaller than the swing angle of the light at the second turning point. The first mirror has a swing angle larger than the swing angle of the light when it is incident on the first mirror from the scanning optical system, and the light incident on the second mirror from the first turning point is said to be the same. The fundus imaging device according to claim 1, wherein the fundus camera is swiveled at a first swivel point. The first mirror forms the first turning point at the focal point of the first mirror.
The fundus photography according to claim 1 or 2, wherein the second mirror has two focal points, and the second turning point is formed at the other focal point by locating the first turning point at one focal point. apparatus. The fundus photography apparatus according to any one of claims 1 to 3, wherein the first mirror is an aspherical mirror having a mirror surface formed of a quadric surface. The first mirror has a convex surface as a reflective surface .
The fundus photography apparatus according to any one of claims 1 to 4, wherein the second mirror has a concave surface as a reflective surface. The fundus photography apparatus according to any one of claims 1 to 5, further comprising an optical member for correcting an inclination of an image plane caused by reflection of the fundus reflected light by the first mirror and the second mirror. The fundus photography apparatus according to any one of claims 1 to 6 , wherein the first mirror corrects an asymmetric curvature of field caused by the second mirror. The scanning optical system is
An SLO optical system having a first optical scanner that scans the light from the first light source and obtaining a frontal image of the fundus by the light from the first light source.
An OCT optical system that has a second optical scanner that scans the measurement light from the second light source and obtains a tomographic image of the eye to be inspected using the principle of optical interference.
The optical path of the SLO optical system and the optical path of the OCT optical system are coupled between the first optical scanner and the first mirror, and between the second optical scanner and the first mirror. The fundus photography apparatus according to any one of claims 1 to 7 , further comprising an optical path coupling member. The fundus photography apparatus according to claim 8 , wherein the SLO optical system and the OCT optical system are telecentric on the object side.