JP3352111B2 - Fundus imaging device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fundus photographing apparatus used in ophthalmic clinics and the like.

[0002]

2. Description of the Related Art Conventionally, there is known a fundus photographing apparatus in which a fundus illumination light beam and a photographing light beam are separated in one direction on a pupil plane of an eye to be examined. Further, in a fundus camera illuminated with a ring light beam, it is known to make a shooting surface horizontally long in order to effectively use a film surface. There is also known a fundus camera that projects a light beam for focusing onto the fundus from both sides of a pupil, and determines focusing based on a relative positional relationship between them. Further, there has been proposed a fundus camera in which two or three photographing apertures are provided on the cornea side at a ring slit conjugate position.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to separate a fundus illumination light beam and a photographing light beam in a vertical direction on a pupil plane of an eye to be inspected, to enable fundus photographing with a small pupil, and to perform vertical photographing with a compound aperture. It is an object of the present invention to provide a fundus photographing apparatus that can prevent flare from entering the anterior eye even when photographing the fundus widely, and that can easily and accurately focus.

[0004]

According to the present invention, there is provided an ophthalmologic image processing apparatus comprising: a portion through which a fundus illumination light beam passes on a pupil of a subject's eye; In a fundus photographing apparatus that performs fundus photographing using an optical system that separates a portion through which a photographing light beam passes in the vertical direction on the pupil plane, a compound diaphragm is provided in the optical system,
The composite diaphragm is disposed at a position conjugate with the pupil plane and passes through the photographing light beam. And a light-shielding portion that is disposed separately in front of and behind the pupil plane with respect to a position conjugate with the pupil plane.

[0005]

The fundus photographing apparatus having the above configuration separates the fundus illumination light beam and the photographing light beam in the vertical direction on the pupil plane of the eye to be examined.
Enables fundus photography with small pupils.

[0006]

FIG. 1 is a block diagram of a non-mydriatic retinal camera according to an embodiment. On the optical axis O1 from the observation light source 1 to the subject's eye E, an infrared filter 2, a condenser lens 3, a mirror 4, an imaging light source 5 composed of a strobe tube, a diaphragm 6 having a crescent-shaped opening, a relay lens 7, a drive Optical axis rotated by means 8
Small mirror 9 that can be inserted into and removed from O1 and outside, relay lens 10, half mirror 11 arranged on one half of the optical path, objective lens 1
2 are sequentially arranged. Behind the half mirror 11,
Two rectangular plate-shaped light shielding plates 13a and 13c, which are provided on the half surface opposite to the half mirror 11, and these light shielding plates 13a and 13c
A composite aperture 13, a focus lens 14, a photographic lens 15, a flip-up mirror 16 that is flipped upward, and a photographic film 17 are sequentially provided. The reflection direction of the flip-up mirror 16 is As shown in FIG. 2, a field lens 18, a mirror 19, a lens 20, and a television camera 21 on which two lines 18a are drawn are provided, and the fundus image can be observed by a television monitor 22.

[0007] In the reflection direction of the small mirror 9, the diaphragm 23 is substantially conjugate with the pupil Ep and has a semi-cylindrical opening 23 a as shown in FIG. 3 (a), and is shown in FIG. 3 (b) substantially conjugate with the fundus Er. A diaphragm 24 having a slit opening 24a, various lenses, and a light source 25 are arranged as described above, and together with the driving means 8 and the small mirror 9, a target for focus detection that moves in the direction of the optical axis O1 in conjunction with the focus lens 14. The projection optical system 26 is configured.

FIG. 4 is a front view of the vicinity of the half mirror 11 as viewed from the direction of the eye E. Between the half mirror 11 and the circular aperture plate 13b, it is arranged on the optical axis to observe the anterior eye. A light source 27 serving as a fixation lamp at the time and a light source 28 for adjusting a working distance are provided on the surface side. Further, an auxiliary lens 29 is disposed behind the objective lens 12 so as to be insertable and removable, and is used for observing an anterior ocular segment.

When performing fundus photography, first, the auxiliary lens 2
9 is inserted into the optical path, the light sources 27 and 28 are turned on, and the television camera 21 is used to observe the anterior eye. As shown in FIG. 5, two marks, circular and crescent, are electrically generated on the television monitor 22 by a symbol generator (not shown), and these marks match the pupil image Ep ′ of the eye E. Alignment as described above. When a certain degree of alignment is achieved, the auxiliary lens 29 is moved out of the optical path and the fundus image is observed, so that the corneal reflection image 28 'of the light source 28 is focused. At this time, an aperture image 6 ′ of the aperture 6 is projected on the half mirror 11 as shown in FIG. 4, and a luminous flux is projected from below the pupil Ep of the eye E to be inspected. There is little fear that the projection light will be blocked.

Next, the driving means 8 is driven, the small mirror 9 is inserted on the optical axis O1, and the light source 25 is turned on. The luminous flux emitted from the light source 25 illuminates the fundus Er, and the fundus reflection light is received by the television camera 21 and projected on the television monitor 22. The optotype projection optical system 26 is moved along the direction of the optical axis O1, and in conjunction therewith, the focus lens 14 is moved while being kept conjugate with the photographic film 17. TV monitor 2
As shown in FIG.
a of image 18a ′ and slit 24a of target projection optical system 26
When the image 24a 'of the image coincides, the image is focused on the photographic film 17.

When the focusing on the photographic film 17 is completed, the small mirror 9 is rotated and retracted out of the optical path.
The flip-up mirror 16 is flipped up, and the photographing light source 5 emits light to perform fundus photographing.

FIG. 6 is an explanatory diagram showing the relationship between the light beam within the eye to be examined and the aperture image. The light beams La, Lb, and Lc that illuminate the three points A, B, and C of the fundus Er pass through the opening of the aperture image 6 'on the pupil Ep and enter the eye E to be examined.
The light becomes La ′, Lb ′, and Lc ′, passes through the composite aperture image, and exits to the outside of the eye E. The composite aperture image is the actual composite aperture 1
The three partial images 13a ', 13c', and 13b 'correspond to the three light-shielding plates 13a and 13c and the circular aperture plate 13b.
Form near Ep.

FIG. 7 is a front view of the pupil Ep, and FIGS. 8 (a), (b),
(c) is an explanatory diagram when the partial images 13a ', 13b', and 13c 'are viewed from the optical axis direction.
FIGS. 8A to 8C show the positional relationship between a 'to 13c' and the fundus reflection light.
As shown in (c), in the partial images 13a 'and 13c', the light beams La 'and Lc' are emitted with the lower and upper portions thereof separated from each other. Separation of the incident light to the eye E and the fundus reflection light in the anterior eye becomes clear, the flare light generated by the corneal reflection and scattering of the illumination light is not mixed, and a fundus image with high contrast can be obtained. The illumination light beam and the reflected imaging light beam at point D on the fundus of FIG. 9 only spread in the horizontal direction in the anterior segment of the eye, and separation can be obtained, so that this direction can be made wider and the screen can be made horizontally long.

The field lens 18 has one line 18a, and the center of the slit image 24a 'and one line 18a
The configuration may be such that a ′ matches. An optical finder can be used. However, if observation is always performed using the television monitor 22, a configuration in which the cursor line is generated electrically without providing the two lines 18a on the field lens 18 is adopted. No problem.

FIG. 10 is a block diagram of a first reference example, in which the focusing system in FIG. 1 is automated. A stop 42 having a slit opening, a lens 43, and a dichroic mirror 44 are provided at a position corresponding to the mirror 4 in FIG. 1 in front of the light source 41 for focusing, and reach the optical axis O1. A dichroic mirror 45 is provided immediately after the composite aperture 13, and a lens 46, a cylindrical lens 47 that forms a linear image, and a one-dimensional line sensor 48 are provided in the reflection direction thereof, and are orthogonal to the one-dimensional line sensor 48. An image is formed in the orientation. A computer 49 is connected to the one-dimensional line sensor 48, and is configured to control driving means 50 for driving the focus lens 14 based on a signal from the one-dimensional line sensor 48. Also, in the incident direction of the dichroic mirror 44,
A lens 51 and an observation light source 52 are provided.

When focusing, the light source 41 is caused to emit light and the light beam is projected onto the fundus Er. The fundus reflected light is a composite aperture 1
The light is reflected by a dichroic mirror 45 behind the lens 3 and passes through a lens 46 and a cylindrical lens 47 to form an image on a one-dimensional line sensor 48 as shown in FIG. Since the cylindrical lens 47 has a refracting power in a direction orthogonal to the one-dimensional line sensor 48, the stop image 42 ′ formed by the stop 42 is a long image perpendicular to the direction of the one-dimensional line sensor 48. Since the light receiving position on the one-dimensional line sensor 48 depends on the diopter of the eye E, the amount of movement of the focus lens 14 is determined from the light receiving position of the aperture image 42 ′ by the aperture 42, and the focus can be adjusted. .

FIG. 12 is a part of a configuration diagram of a second reference example having a scaling function. On the optical axis O2 in front of the imaging light source 5, as shown in FIG. 13, an illumination stop 53 having a crescent-shaped opening 53a eccentrically arranged with respect to the optical axis O2, a relay lens 7, and as shown in FIG. The shutter 54b includes a rectangular opening 54a and two shutters 54b and 54c.
The field stop 54, the relay lens 10, and the half mirror 1 whose size of the opening can be freely changed by moving the mirror 54c
1 are sequentially arranged. Behind the optical path O3 in front of the subject's eye E, a pupil conjugate imaging diaphragm 55 having a circular opening 55a as shown in FIG. 15 and moving in a direction perpendicular to the optical axis O3 as shown in FIG. Each one before and after the diaphragm 55
A total of two light-shielding plates 56 and a photographing lens 57 provided for each
Are arranged, and the photographing film 17 is reached. The illumination diaphragm 53 and the two light shielding plates 56 are movable on the optical axis in a direction perpendicular to the optical axis, and are configured to move as the magnification is changed.

At the time of wide-angle photographing, the two shutters 54b and 54c of the field stop 54 are opened to enlarge the field of view. Since the angle of view of the photographing light beam becomes large, the illumination aperture 53 and the light shielding plate 56
Is moved so that the separation amount of the illumination light beam and the photographing light beam on the pupil Ep becomes large. Note that a circular aperture stop may be used as the light shielding plate 56, but it is preferable to use a light shielding plate in only one direction because peripheral dimming occurs. Also, the light shielding plate 56
It is desirable to use two sheets, and in this embodiment, two light shielding plates 56 are used. However, even if only one sheet is used, a certain degree of effect can be obtained. Further, it is preferable that the field stop 54 is configured to be linked to a mechanism that keeps the eye fundus conjugate with the fundus in the optical axis direction.

FIG. 17 is a front view of the photographic stop 59 in the third embodiment capable of performing stereo observation and photography. The photographing diaphragm 59 is used in place of the illumination diaphragm 53 in FIG. 12. The monocular portion 59a and the binocular portion 59b are provided on the same plate, and switching between monocular observation and binocular observation is performed by sliding the plate. Will be FIG. 18 is a diagram showing the light flux on the pupil Ep during stereo observation. Illumination flux
Ld and the luminous flux Le are separated vertically and horizontally.

At the time of stereoscopic observation, the one-dimensionally configured light-shielding plate 56 and illumination stop 53 in the second reference example may be used as they are. It is needless to say that in the case of the stereo observation photographing, a stereo observation mirror or a stereo film camera for forming the left and right images by dividing the optical path into left and right at the pupil conjugate position is separately required.

FIG. 19 is a structural view of a main part of a fundus photographing apparatus according to a fourth reference example. Optical axis O4 in front of light source 61
On the top, a ring slit 62 having a ring-shaped opening,
A lens 63 and a perforated mirror 64 having an opening at the center are provided, and the eye E to be examined is positioned in the reflection direction of the perforated mirror 64. On the optical axis O5 in front of the subject's eye E, two circular apertures 6 arranged before and after a conjugate image 62 'of a perforated mirror 64 and a ring slit 62 and having a circular opening at the center.
5 and 66 are provided, leading to an imaging and observation optical system (not shown).

FIG. 20 is an explanatory diagram showing the positional relationship of the image projected on the pupil Ep, and shows a case where the pupil diameter is small. Since the pupil diameter is smaller than the ring slit image 62 ′, the ring slit image 62 ′ forms an image concentrically.
And the stop images 65 'and 66' are at positions eccentric to the pupil Ep.

FIG. 21 is a longitudinal sectional view of the eye E, and shows a state of a light beam inside. An image 62 'of the ring slit 62 is formed in the upper part of the eye E, and images 65' and 66 'of circular stops 65 and 66 are formed in the lower part. The illumination light beams Lf, Lg, Lh that illuminate the attention points F, G, H on the fundus are three images 62 ′, 65 ′, 6
6 ′ is partially shielded, and the illumination light beams Lf, Lg, Lh and the fundus reflection light Lf ′, Lg ′, Lh ′ are completely separated in the optical path in the anterior segment of the eye, and scattering and flare do not occur. Absent.

Although the illumination light beam in FIG. 21 shows a light beam in a vertical cross section, the degree of separation between the illumination light beam and the photographing light beam in the horizontal cross section is almost the same as the center. Since the illumination light beam is shielded only by the ring slit 62, the illumination light is uniformly illuminated without blurring of the fundus Er. The light blocking by the circular diaphragms 65 and 66 is appropriate to be about 20 to 30% of the central light beam diameter. At this time, the luminance of the central part is about half of the luminance of the peripheral part, but at this level, the illumination unevenness is not so noticeable. It should be noted that illumination unevenness may be controlled automatically by film surface reflection. If the illumination is uniform, more appropriate exposure can be performed by performing photometry using center-weighted photometry.

When photographing the periphery of the fundus, the pupil is observed obliquely. At this time, the apparent pupil shape becomes an ellipse as shown by Ep ′ in FIG. Even in the case of the eccentric illumination, the light amount and the uniformity are not different from those in the case of the central portion photographing, and proper exposure can be performed. In addition, when the line of sight is swung up and down, the image may be taken eccentrically in the left and right direction.

FIGS. 22 and 23 are explanatory views of the aperture system of the fundus photographing apparatus shown in FIG. 19 having a variable angle of view optical system. FIG. 22 shows the vicinity of the ring slit 62, and FIG. Is shown in the vicinity. In the vicinity of the optical axis O4, two types of large-size slits 71 and small-size slits 72, which are different in size, are removably inserted at different positions on the optical axis O4. 71 is inserted, and a narrow-angle slit 72 is inserted during narrow-angle shooting. In the hole of the perforated mirror 64, a cylindrical portion 73 for guiding a light beam is provided along the optical axis O5.
A circular diaphragm 74 having a circular opening is provided at the tip of the eye E side. Further, a sliding cylinder portion 76 which slides in the direction of the optical axis O5 with respect to the cylinder portion 73 and has a circular diaphragm 75 at the end on the photodetector side is provided.
4 is variable.

At the time of wide-angle photographing, the wide-angle slit 71 is inserted on the optical axis O4, and the sliding cylinder 76 is pushed toward the perforated mirror 64 to reduce the distance between the circular apertures 74 and 75. When the distance between the circular stops 75 is reduced, no shaking occurs even if the angle of view is increased. At the time of narrow-angle shooting, the wide-angle slit 71 and the narrow-angle slit 72 are exchanged, and
To increase the distance between the circular apertures 75 and 74.

When the pupil diameter is large, the pupil Ep and the ring slit image 62 'may be concentrically illuminated as in the prior art. The circular stop 75 is not of a sliding type, but may be provided separately for a narrow-angle lens and a wide-angle lens, and may be configured to be alternately inserted into and removed from the optical axis in accordance with the purpose of photographing. Further, in order to separate the optical path, it is more preferable to provide a variable field stop in the illumination optical system and change the field stop according to a change in the angle of view.

FIG. 24 is an explanatory diagram showing the relationship of the light flux on the pupil of the non-mydriatic retinal camera. The illumination stop (not shown) has a crescent shape, and a crescent-shaped stop image 77 and a photographing light beam image 78 are formed on the pupil Ep. Since only the rear pole portion is photographed, the illuminating light flux may be determined in a certain direction, and the photographing may be always performed with eccentricity.

In the above embodiment, the fundus camera has been described. However, the present invention can be applied to a fundus photographing apparatus used only for observation. In this case, the objective lens may be separated and held like an indirect mirror. .

[0031]

As described above, the fundus photographing apparatus according to the present invention separates the fundus illumination light beam and the photographing light beam in the up-down direction on the pupil plane of the eye to be inspected, enables fundus photographing with a small pupil, and provides a composite aperture. Accordingly, even when the fundus is photographed widely in the vertical direction, focusing can be performed accurately and easily without causing flare in the anterior segment.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an embodiment.

FIG. 2 is a field lens.

FIG. 3 is a front view of the stop.

FIG. 4 is a front view of a half mirror unit.

FIG. 5 is an explanatory diagram of marks on a television monitor.

FIG. 6 is an intraocular light path diagram.

FIG. 7 is a front view of a pupil.

FIG. 8 is a light beam cross-sectional view of a pupil plane and a stop plane.

FIG. 9 is an explanatory diagram of a fundus oculi.

FIG. 10 is a configuration diagram of a first reference example.

FIG. 11 is an explanatory diagram of a slit light beam on a CCD.

FIG. 12 is a configuration diagram of a second reference example.

FIG. 13 is a front view of an illumination stop.

FIG. 14 is a front view of a field stop.

FIG. 15 is a front view of a photographing aperture.

FIG. 16 is a front view of an imaging system light shielding plate.

FIG. 17 is a front view of a stereo stop.

FIG. 18 is an explanatory diagram of a light beam during stereo shooting.

FIG. 19 is a configuration diagram of a main part of a fourth reference example.

FIG. 20 is a front view of a pupil.

FIG. 21 is an intraocular light path diagram.

FIG. 22 is a layout view of a ring slit.

FIG. 23 is a layout diagram of a circular stop.

FIG. 24 is a light beam arrangement diagram on a pupil in a non-mydriatic retinal camera.

[Description of Signs] 11 Half mirror 13 Composite stop 13a, 13c, 56 Light shield 13b Circular aperture 53 Lighting stop 54 Field stop 55 Shooting stop 62 Ring slit 64 Perforated mirror 65, 66, 74, 75 Circular stop

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-55-29316 (JP, A) JP-A-62-133931 (JP, A) JP-A-54-50186 (JP, A) 27293 (JP, A) JP-A-58-25142 (JP, A) JP-A-63-212324 (JP, A) JP-A-61-37131 (JP, A) JP-A-4-256726 (JP, A) JP-A-5-15497 (JP, A) Jikken 44-15679 (JP, Y1) (58) Fields investigated (Int. Cl. ⁷ , DB name) A61B 3/00-3/16

Claims (2)

(57) [Claims] A fundus using an optical system that separates, in an up-down direction on a pupil plane, a portion through which a fundus illumination light beam passes on a pupil of a subject's eye and a portion through which a photographing light beam reflected from the fundus passes to photograph the fundus. In a fundus imaging apparatus that performs imaging,
The optical system is provided with a compound stop, and the compound stop has a pupil plane and
An aperture plate disposed at a conjugate position through which the photographing light beam passes, and a light shielding and separating light beam at a position corresponding to a portion where the illumination light beam and the photographing light beam overlap in the anterior eye part .
To separate the position conjugate with the pupil plane back and forth in the optical axis direction.
A fundus photographing apparatus, comprising: a light-shielding portion arranged in a vertical direction. 2. The composite aperture according to claim 1, wherein said composite aperture is a photographing aperture.
A fundus photographing apparatus according to claim 1.