JP2001346764A - Eyeground camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ophthalmological device capable of precisely positioning a subject eye to an instrument main body, and receiving an image of favorable precision even when a front eye part observing condition is changed to/from an eyeground observing condition. SOLUTION: An illumination flux is projected toward a subject eye E by an illumination optical system 1, an eyeground or a front eye part is observed based on reflection flux reflected by a subject eye E in an observation optical system 2, an alignment flux is projected on the eye E by an alignment optical system 3, the alignment flux is provided to a pupil EP of the eye E in an optically pupil-parted state by a pupil parting member 34 disposed at a position roughly conjugated with the pupil EP of the eye E, and a front eye part observing condition and an eyeground observing condition are set by change by a changing lens 19 detachably inserted into an optical path of the observation optical system 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for projecting an alignment light beam toward an eye to be inspected when observing or photographing the eye to be inspected, and based on the reflected light flux of the alignment light beam with respect to the eye to be inspected, relative to the apparatus main body. The present invention relates to a fundus camera that performs positioning.

[0002]

2. Description of the Related Art Conventionally, in a fundus camera, it is necessary to accurately adjust the relative position of the fundus camera with respect to the eye to be examined. For this reason, the alignment light beam is projected toward the eye to be inspected, and the alignment is detected based on the imaging state of the corneal reflection luminescent spot.

For example, in a fundus camera disclosed in Japanese Patent Application Laid-Open No. 8-275921, an alignment index light is projected on an eye to be inspected, and a light spot by reflected light of the alignment index light and an anterior eye image are displayed on a monitor screen. The alignment operation is completed while visually checking the alignment status at the initial stage of the machine operation.

Simultaneously with this alignment operation, the index light is made incident on the eye to be examined from a direction of 45 degrees, and the reflected light flux of the index light incident on the eye is formed on the light receiving element.
By operating the drive system based on the image forming position, the operation distance adjustment operation is completed.

When the alignment operation is completed, the switching unit including the concave lens and the mirror is retracted from the photographing optical axis to switch from the state of observing the anterior segment of the subject's eye to the state of observing the fundus of the subject's eye. Is projected onto the fundus of the subject's eye by the focusing index projection optical system, the fundus reflected light beam is imaged on the TV camera by the fundus imaging optical system, and the focus lens of the fundus imaging optical system is moved to focus. Perform the operation.

[0006] When the completion of focusing is detected, the focusing index light source is turned off, and then the strobe discharge tube emits light to photograph a fundus image with a television camera.

[0007]

In the fundus camera described above, since only one index light is presented to the subject's eye for performing the alignment operation and the working distance adjustment operation, it is difficult to detect the alignment and the working distance. There has been a problem that accuracy is difficult to obtain.

If the accuracy of the alignment and the detection of the working distance is poor, the switching unit including the concave lens and the mirror is retracted from the photographing optical axis and the optical path from the anterior ocular segment observation optical system to the fundus photographing optical system. In the case of switching, not only the blur of the fundus image is large, but also it takes time for focus detection, and there is a problem that the burden on the patient is large.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a fundus camera capable of accurately and promptly aligning a subject's eye with an apparatus body.

[0010]

According to a first aspect of the present invention, there is provided a fundus camera configured to project an illumination optical system for projecting an illumination light beam toward an eye to be inspected, and a reflected light beam reflected by the eye to be inspected. An observation optical system for observing the fundus or anterior segment of the eye to be inspected, and a pupil division member that projects an alignment light beam and presents the alignment light beam to the pupil of the eye under optical pupil division with the pupil of the eye to be inspected; An alignment optical system disposed at an appropriate position, and a switching lens for switching between a state of observing the fundus of the eye to be examined and a state of observing the anterior segment of the eye to be examined being inserted / removed into the optical path of the observation optical system. The gist is that

According to such a configuration, it is possible to perform an alignment operation based on the alignment luminous flux divided by the optical pupil, and to switch between the anterior eye image of the eye to be examined and the fundus image of the eye to be examined. However, an accurate image can be received.

A fundus camera according to a second aspect of the present invention includes an alignment optical system having a photoelectric sensor for receiving a reflected light beam emitted from the alignment light source and reflected by the eye to detect an alignment state. Make a summary.

According to such a configuration, since the alignment reflected light beam is received by the photoelectric sensor different from the image receiving element for observation and photographing, the resolution at the time of alignment detection can be improved.

According to a third aspect of the present invention, the fundus camera includes a driving unit for automatically performing relative positioning with respect to the subject's eye based on a reflected light beam emitted from the alignment light source and reflected by the subject's eye. The point is that

According to such a configuration, it is possible to automatically position the eye to be examined with the apparatus main body while maintaining high accuracy.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a fundus camera according to the present invention will be described with reference to the drawings as applied to a fundus camera.

In FIG. 1, reference numeral 1 denotes an illumination optical system, 2 denotes a photographing and observation optical system, and 3 denotes an alignment light beam projection optical system.

(Illumination optical system 1) The illumination optical system 1 includes an observation light source 11, a condenser lens 12, a dichroic mirror 13, a corneal stop 14, an iris stop 15, a crystalline lens stop 16,
Relay lens 17, perforated mirror 18, switching lens 1
9, an oblique half mirror 20, and an objective lens 21.
The corneal diaphragm 14 is conjugate with the cornea C, and the iris diaphragm 15
Is conjugate with the pupil EP of the eye E, the lens stop 16 is conjugate with the rear surface of the lens (not shown) of the eye E, and the aperture mirror 18 is arranged at a position conjugate with the pupil EP with respect to the objective lens 21. Have been. The dichroic mirror 13 has a characteristic of transmitting visible light and reflecting infrared light.

The illumination light beam from the observation light source 11 passes through a condenser lens 12, a dichroic mirror 13, and a corneal diaphragm 14, an iris diaphragm 15, and a crystalline lens diaphragm 16. The iris diaphragm 15 is a perforated mirror 1 with respect to the relay lens 17.
8, the image of the iris diaphragm 15 is once formed near the apertured mirror 18 via the relay lens 17. The ring-shaped illumination light beam reflected by the aperture mirror 18 passes through the switching lens 19 and the half mirror 20, forms an image near the pupil EP of the eye E by the objective lens 21, and illuminates the eye E.

The illumination optical system 1 includes a photographing light source 22 and a condenser lens 23 behind the dichroic mirror 13.
Having. In the case of photographing, the photographing light source 22 emits light by operating a photographing switch (not shown). The photographing light from the photographing light source 22 passes through the condenser lens 23 and the dichroic mirror 13 and is guided to the eye E in the same manner as the illumination light from the observation light source 11.

Further, the switching lens 19 is detachable from the main optical path of the main optical axis O1, and as shown in FIG.
In a state where the light sources are separated from the main optical path, the light sources 11 and 22
Is formed on the fundus EF of the eye E to be examined.

(Shooting and Observing Optical System 2)
Is an objective lens 21, a half mirror 20, a switching lens 1
9, a perforated mirror 18, a focusing lens 24, a quick return mirror 25, a field lens 26, a dichroic mirror 27, a relay lens 28, an imaging tube 29, and a monitor 30.

The focusing lens 24 has a function of moving along the main optical axis O1 (see the arrow) so as to adjust the focus in accordance with the degree of the refractive error of the eye E.

The reflected light from the eye E is transmitted to the switching lens 19.
Is inserted in the main optical path O1, the objective lens 2
1. After an image is formed once via the half mirror 20 and the switching lens 19, it passes through the hole 18a of the perforated mirror 18,
The light is reflected by the quick return mirror 25 via the focusing lens 24, is received by the imaging tube 29 via the field lens 26, the dichroic mirror 27, and the relay lens 28, and the anterior ocular segment image E ′ is displayed on the screen of the monitor 30. You.

Further, when the switching lens 19 is separated from the main optical path O1, the objective lens 21 causes the fundus EF to be moved.
The image is once formed in the vicinity of the hole 18a of the aperture mirror 18 which is substantially conjugate with the aperture mirror 18a, passes through the hole 18a of the aperture mirror 18 and passes through the focusing lens 24 to form the quick return mirror 2
5 through a field lens 26, a dichroic mirror 27, and a relay lens 28.
And the fundus image EF ′ is displayed on the screen of the monitor 30.

On the other hand, the observation / photographing optical system 2 is provided with a film 31 at a position conjugate with the field lens 26 with respect to the quick return mirror 25.
The quick return mirror 25 separates from the optical path of the photographing optical system 2 at the same time as the light is emitted (the broken line state in FIG.
In step 1, a fundus image EF 'is recorded.

Therefore, when the switching lens 19 is inserted into the main optical path O1 when the fundus EF and the imaging tube 29 and the film 31 are in a conjugate relationship, the pupil EP of the eye E and the imaging tube 29
And the film 31 are arranged at a conjugate position. For this reason, the examiner determines the main optical path O1 of the switching lens 19.
By switching between insertion and removal from the eye, the fundus EF and the pupil EP of the eye E can be switched and observed.

(Alignment Beam Projection Optical System 3) The alignment beam projection optical system 3 includes an alignment light source 32, a field stop 33, a pupil dividing member 34 arranged near a conjugate position with the pupil EP of the objective lens 21, a collector lens 35,
A half mirror 20 and an objective lens 21 are provided.

As shown in FIG. 3B, the pupil dividing member 34 has two (in this case) openings 34a and 34b for forming an alignment luminescent spot (described later).

The alignment light beam emitted from the alignment light source 32 is split by the openings 34a and 34b of the pupil splitting member 34 while being restricted by the field stop 33.
Focus R of the objective lens 21 via the collector lens 35
After being focused once, the light is reflected by the half mirror 20 and is projected parallel to the eye E through the objective lens 21.

This alignment index light beam forms a virtual image near the pupil EP. This virtual image is, like the reflected light flux from the eye E of the illumination optical system 1, the objective lens 21, the half mirror 20, the switching lens 19, the aperture mirror 18, the focusing lens 24, the quick return mirror 25, and the field lens 26. , Dichroic mirror 27, relay lens 2
The image is formed on the image pickup tube 29 via 8.

This virtual image is displayed on the monitor 30 as alignment bright points a and b. While observing the alignment bright points a and b on the monitor 30 while observing the alignment, the examiner operates an operating rod such as a joystick provided on the apparatus main body (not shown) so that the alignment bright points a and b approach. The apparatus main body is aligned with the eye E to be inspected.

Here, when alignment is completed, the relative positions of the eye E and the apparatus main body (not shown) in the horizontal direction (x direction), the vertical direction (y direction), and the front and rear direction (z direction) are appropriate. As shown in FIG. 4A, the alignment bright points a and b observed on the monitor 30 coincide with the center and become one point.

When there is a displacement (Δz) in the depth direction of the apparatus main body with respect to the eye E, the alignment bright spots a and b are separated, and when there is a displacement (Δy, Δx) in the vertical direction. 5A, the midpoint M of the alignment luminescent spots a and b is shifted from the reference position of the image pickup tube 29, as shown in FIG. Here, T is the monitor 30 corresponding to the reference position of the imaging tube 29.
In the alignment index (alignment OK area) optically or electrically displayed on the screen 30a of the above, the examiner indicates the alignment luminescent spots a and b in the alignment index T.
Perform the alignment operation so that

Then, while observing the anterior eye image E 'displayed on the screen 30a, the apparatus main body is moved so that the apparatus main body (not shown) and the eye E have a predetermined positional relationship, and the alignment is completed. Later, when focusing adjustment (Z direction) is completed using focusing adjustment assisting means (not shown), photographing of the fundus EF is performed.

At the time of photographing the fundus EF, when the focusing adjustment by the focusing adjustment assisting means is completed, the switching lens 19 is detached from the main optical path O1, the alignment light source 32 is turned off at the same time, and the quick return mirror is turned off. The shooting light source 22 emits light at the same time when 25 jumps up, and a fundus image EF ′ is recorded on the film 31.

If the half mirror 20 is also retracted together with the switching lens 19, more light flux returns to the photographing optical system, and the number of factors causing flare, ghost, and the like is reduced. Next, an example in which the amount of alignment deviation is obtained based on the signal of the photoelectric sensor (the imaging tube 29) will be described.

In the example of signal output when the alignment is completed as shown in FIG. 4A, one peak P having a high light quantity can be obtained as shown in FIG. 4B.

On the other hand, when there is a shift in the xy directions, the shift amounts Δx and Δy can be obtained from the shift amount from the reference position (pixel) of the image pickup tube 29.

On the other hand, as shown in FIG. 5A, when there is also a shift in the z direction, as shown in FIG. 5B, two low peaks P1 and P2 of the light amount are obtained. P
The shift amount Δz can be obtained from the separation amount of the alignment bright points a and b based on the separation distance between P1, P2 and the light amount.

At this time, as shown in FIG.
The apertures 34a, 34b of 4 are limited by the rotary light-shielding plate 36 so that the alignment light beam is also time-divided, and the alignment luminescent spots a, which are presented alternately with the reference position.
It is possible to detect the direction of the shift amount Δz from the positional relationship of the middle point M of b.

It is also possible to use a plurality of alignment light sources at the position of the pupil division member 34 to reproduce the pupil-divided alignment light beam, and to perform time division by the lighting time of the light source.

As shown in FIG. 7, a quick return mirror 25 is provided to improve the resolution of the alignment light beam.
A half mirror 37 is provided between the lens and the field lens 26. The half mirror 37 divides the alignment reflected light beam from the eye E and forms an image on the photoelectric element 39 by the relay lens 38.
May be separately provided to improve the resolution at the time of alignment detection by the optical magnification or the resolution of the photoelectric element 39 itself.

When such an alignment detecting optical system 4 is provided, it is difficult for the examiner to perform an alignment operation because z
Since the alignment operation (focusing operation) is performed in the direction, if the photoelectric element 39 is a line sensor such as a one-dimensional CCD, a focusing index for presenting the deviation amount Δz to the examiner is displayed on the screen 30a. The operability is improved with just one.

Further, the light amount of the alignment reflected light beam imaged on the photoelectric element 39 is calculated, and a drive means for automatically controlling the apparatus body based on the light amount value is provided, so that an automatic alignment operation is performed. Is also possible. After that, it is of course possible to automatically take a picture.

In the above-described embodiment, the recording is performed on the film 31. However, photographing is performed using a relay lens (not shown) and a television camera (still image recording / moving image recording).
May be performed. Further, although the configuration is such that the eye E is observed on the screen 30a, the configuration may be such that the eye E is observed with an eyepiece.

Further, with respect to the quick return mirror 25, the illumination optical system 1 and the alignment optical system 3 may be configured as infrared optical systems so that a fixed dichroic mirror performs wavelength division with the photographing system. Absent.

Although the pupil-divided alignment light beam is formed into an image at the center of the pupil EP (coincident with the center M on the screen 30a), as shown in FIG. It is also possible to project a plurality of alignment luminous fluxes onto the light source.

When the alignment light beam forms an image other than at the center M, the position (distance) that matches from the center M changes depending on the curvature of the eye E to be examined.

Therefore, as shown in FIG. 8A, the alignment indices Tmu, Tmb, Tmr, and Tml are displayed on the screen 3 so that the upper, lower, left, and right positions can be easily grasped even when the imaging position changes.
It is good to display it at 0a.

As shown in FIG. 8B, if the alignment light beam is presented in a time-divided manner, the midpoints Ma and Mb between the divided alignment bright points a and b are detected by the sensor (the imaging tube 29). Alternatively, when the position coincides with the reference position on the photoelectric element 39), the alignment is completed, and the automatic detection of the completion of the alignment is facilitated.

[0052]

As described above, the fundus camera according to the first aspect of the present invention provides an illumination optical system for projecting an illumination light beam toward an eye to be inspected, and a fundus camera based on the light beam reflected by the eye to be inspected. An observation optical system for observing the fundus or the anterior segment, and a pupil dividing member that projects an alignment light beam and presents the alignment light beam to the subject's pupil in a state where the alignment light beam is divided into optical pupils is disposed at a position substantially conjugate with the subject's pupil. Alignment optical system, by including a switching lens that switches between a state of observing the fundus of the eye to be examined and a state of observing the anterior segment of the eye to be examined being inserted / removed into the optical path of the observation optical system,
Alignment operation can be performed based on the alignment luminous flux divided by the optical pupil, and an accurate image can be received even when the anterior eye image of the eye to be examined and the fundus image of the eye to be examined are switched. Can be.

A fundus camera according to a second aspect of the present invention includes an alignment optical system having a photoelectric sensor for detecting an alignment state by receiving a reflected light beam emitted from the alignment light source and reflected by the eye to be inspected. The resolution at the time of alignment detection can be improved.

According to a third aspect of the present invention, the fundus camera includes a drive unit for automatically performing relative positioning with respect to the subject's eye based on a reflected light beam emitted from the alignment light source and reflected by the subject's eye. Accordingly, it is possible to automatically perform alignment with the apparatus body with respect to the subject's eye while maintaining high accuracy.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a fundus camera according to an embodiment of the present invention and illustrating an optical system in an anterior segment observation state.

FIG. 2 is an explanatory diagram of an optical system in a fundus observation state.

FIG. 3A is an explanatory diagram of an optical system in a state where an alignment light beam is presented to an eye to be inspected, and FIG. 3B is a front view of a pupil dividing member.

4A is a front view of a screen of an anterior ocular segment display at the time of completion of alignment, and FIG. 4B is a graph of a light amount distribution at the time of completion of alignment corresponding to FIG. 4A;

5A is a front view of an anterior segment display screen before alignment is completed, and FIG. 5B is a graph of a light amount distribution before alignment corresponding to FIG. 5A.

FIG. 6 is a front view of a main part when a time difference is provided in optical pupil division.

FIG. 7 is a diagram illustrating a modification of the fundus camera according to the embodiment of the present invention, and is an explanatory diagram of an optical system in an anterior ocular segment observation state when a photoelectric sensor for alignment detection is separately provided.

FIG. 8 shows another modified example of the fundus camera according to the embodiment of the present invention, wherein (A) shows an anterior ocular segment before completion of alignment when the pupil-divided alignment light beam is presented to the subject's eye while being divided. FIG. 8A is a front view of a display screen, and FIG.
FIG. 7 is a graph of a light amount distribution before the completion of alignment corresponding to FIG.

[Explanation of symbols]

 E: eye to be examined EP: pupil 1: illumination optical system 2: photographing optical system 3: alignment optical system 4: alignment detection optical system 19: switching lens 34: pupil division member

Claims (3)

[Claims] An illumination optical system for projecting an illumination light beam toward an eye to be inspected, an observation optical system for observing a fundus of the eye to be inspected or an anterior segment based on a light beam reflected by the eye to be inspected, and an alignment light beam. An alignment optical system in which a pupil dividing member for projecting and presenting the alignment light beam to the pupil of the eye under optical pupil division is arranged at a position substantially conjugate with the pupil of the eye to be inspected, and inserted / removed into the optical path of the observation optical system A fundus camera comprising: a switching lens configured to switch between a state in which the fundus of the eye to be examined is observed and a state in which the eye of the eye to be examined is observed. 2. The apparatus according to claim 1, further comprising an alignment optical system having a photoelectric sensor for detecting a state of alignment by receiving a reflected light beam emitted from said alignment light source and reflected by an eye to be inspected. Fundus camera. 3. The apparatus according to claim 1, further comprising a driving unit for automatically performing relative positioning of the apparatus main body with respect to the subject's eye based on a reflected light beam emitted from the alignment light source and reflected by the subject's eye. The fundus camera according to claim 1.