JPS59189825A - Ophthalmic machine equipped with eyelid position detecting function - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ophthalmological instrument equipped with a pupil position detection function that detects the presence of an eyelid by measuring light reflected from the iris that adjusts the size of the pupil of the eye to be examined.

Fundus photography is frequently performed not only in ophthalmology, but also in internal medicine, neurology, and other medical treatments. Recently, with the spread of mass medical examinations, non-mydriatic fundus cameras that use infrared light have become popular, as they are easy to use and do not cause discomfort or the risk of seizures due to mydriatic drops.

The principle of photographing with this non-mydriatic fundus camera is that instead of forcibly dilating the pupils with mydriatic drops, we wait for the subject's spontaneous mydriasis in a dimly lit room, and use infrared light that is invisible to the eye. This method uses a method in which, after focusing for observation, a photographic light source such as a strobe is emitted to take a photograph.

For this reason, once the photographing light source is turned on, the iris of the eye to be examined undergoes miosis, and it takes time to photograph the eye again. On the other hand, if the eyelids blink during a photo shoot, the photo shoot will fail, but if the photographer does not notice that the subject blinked, it may not be known until the film is developed. Furthermore, even if the user notices blinking, there is the disadvantage that re-photographing the blink takes a considerable amount of time due to pupil miosis.

An object of the present invention is to solve the above-mentioned problems and detect the presence of an eyelid covering the eye to be examined using a light beam for eyelid detection that is imaged on the iris that adjusts the size of the pupil of the eye to be examined. The object of the present invention is to provide a device for illuminating the eye to be examined, especially an ophthalmological instrument equipped with a pupil position detection function that can stop the emission of light from a photographing light source during imaging. In addition to the system, the method includes a means for projecting a light beam for eyelid detection onto the eye to be examined, and the reflected light from the iris of the eye to be examined or its vicinity is guided to a photoelectric conversion means to measure the reflected light. This is characterized by detecting whether or not the eyelids are within the range necessary for an ophthalmological examination.

The present invention will be explained in detail based on illustrated embodiments.

FIG. 1 is a configuration diagram showing an example of the optical system of a fundus camera. 1 is a U chamber light source consisting of a tungsten lamp, etc. The light emitted from this observation light source 1 is transmitted through a condenser lens 2, an infrared light source, etc. A transmission filter 3, a photographing light source 4 consisting of a xenon discharge tube, etc., and a mirror 6 via a condenser lens 5.
is incident on the ring slit plate 7, where it is deflected and sequentially
It reaches the perforated mirror 10 via the relay lens 8.9. The light incident on the perforated mirror 10 from the above-mentioned illumination optical system is reflected by the perforated mirror lO in the direction of the eye E to be examined, illuminates the fundus Ef of the eye E, returns to the original optical path, and then returns to the perforated mirror 10. and reaches the observation optical system. An objective lens 11 is arranged between the perforated mirror 10 and the subject's eye E, and behind the perforated mirror 10, along the optical axis, there are a focusing lens 12, a photographing lens 13, a flip-up mirror 14, A shutter 15 and a photographic film 16 are arranged in sequence. Further, on the reflection side of the flip-up mirror 14, field lenses 17 are placed sequentially along the optical axis at positions conjugate with the photographic film 16.
, a mirror 18 for changing the optical path, a relay lens 19, and an image pickup tube 20 are arranged.

In this fundus camera, the illumination light source 1 and the photographing light source 4 are substantially conjugate with respect to the condenser lens 2, and the observation light source 1 is turned on during observation, and the photographing light source 4 is turned on instantaneously during photography. The light source image is once formed near the ring slit plate 7 by another condenser lens 5, and then an image of the annular opening of the ring slit plate 7 is formed near the perforated mirror 10 by the relay lens 8.9. The illumination light is reflected and travels to the left. After forming an image of the annular aperture near the iris of the eye E with the objective lens 11, the fundus Ef
to illuminate.

The reflected light from the fundus Ef travels to the right, and after being once imaged by the objective lens 11, it passes through the perforated mirror 10 and is focused and imaged by the focusing lens 12 and the photographing lens 13. During observation, the fundus image is guided upward by the flip-up mirror 14 located at the solid line position, and is observed via a relay lens 19 and an image pickup tube 20 by a =7V monitor (not shown), and during photography, the flip-up mirror 14 is positioned at the dotted line position. The fundus image is formed on the photographic film 16 via the shutter 15 which is instantaneously opened.

Reference numeral 21 denotes a light source for eyelid detection, and a projection lens 22 is disposed on the optical path toward the eye E to be examined, and the reflected light from the eye E is transmitted through an objective lens 11 to a light receiving element 23 consisting of, for example, a linear sensor. It is designed to be incident. The projection light from the eyelid detection light source 21 is made to form an image on the iris of the eye E to be examined by the projection lens 22, and the arrangement of the light receiving element 23 that receives the reflected light is such that it is conjugate with the iris with respect to the objective lens 11. It is said to be the location. Further, the lamp 24 is turned on when the photographing light source 4, which was prepared to emit light, stops emitting light.

Figure 2 shows the eyelid detection spot image on the surface of the iris Ei and the position of the fundus illumination light for observation and photography, where Pl is inscribed in the dilated pupil of the subject's eye E. Ring-shaped fundus illumination light P2 is a spot image produced by the illumination light source 21. FIG. 3 shows a state in which the eyelid E1 is lowered, and the eyelid detection spot image P2 illuminates the eyelid El.

Figure $4 shows the relationship between the reflected spot image P2' on the light receiving element 23 and the light receiving element 23, and when the eyelid El is raised, the output of the light receiving element 23 has a large amount of reflection from the iris Ei. Therefore, a clear level difference occurs depending on the presence or absence of the reflected spot image P2', and the output is in the state shown in A. Reflection spot image P2 of eyelid E1 lowering and iris Ei
' disappears, the reflected spot image P2' becomes only the scattered light from the surface of the eyelid E1, and the reflected spot image P2' becomes only the scattered light from the surface of the eyelid E1.
2' is no longer clearly imaged, and as in output B, the level difference between the peak and valley becomes unclear. - Therefore, by measuring the level difference between the peak and valley of the outputs A and B, it is possible to determine the presence of the eyelid El.

The fundus illumination light P1 and the eyelid detection spot image P2 are separated by separating these positions as shown in FIGS. 2 and 3, and at the same time by using different wavelength ranges for each, for example, as shown in FIG. It is also effective to set the fundus illumination light P1 in the infrared light region Z1 and to set the spot image P2 in the region Z2 having a longer wavelength than that. Further, the illumination light P1 and the spot image P2 may not be separated spatially, but may be separated spectrally.

In addition, in order to clearly distinguish the eyelid detection light flux from the fundus illumination light and other external light, the eyelid detection light source 21 emits light in a pulsed manner and frequency modulates it, and a bandpass filter tuned to this is installed in the light receiving section. It may also be inserted into an electrical circuit.

FIG. 6 shows a second embodiment, in which a mask 25 having a circular aperture is placed between the eyelid detection light source 21 and the projection lens 22, and the reflected spot image P2' from the iris Ei passes through the light receiving lens 26. The light is guided to the light receiving element 23 through the light receiving element 23.

FIG. 7 shows a third embodiment, in which a beam splitter 27 is inserted between the mask 25 and the projection lens 22, and the reflected spot image 22' from the iris Ei is transmitted to the projection lens 22.
The light is received by the light receiving element 2 via the beam splitter 27.
It is designed to lead to 3.

In the above-described embodiment, the eyelid El is determined by the pupil position detection mechanism.
is determined to exist in a range that is inconvenient for optometry,
By creating an electric circuit that does not emit the photographing light i4 even when the photographing button of the fundus camera is pressed, it is possible to eliminate the photographing failure caused by @E1. Further, at the same time when the photographing light source 4 stops emitting light, the photographer can be informed that re-photographing is possible by turning on a buzzer or a lamp 24 built into the fundus camera.

As explained above, the ophthalmological instrument equipped with the pupil position detection function according to the present invention can detect the eyelids by using an illumination light source for eyelid detection that forms an image on the iris in addition to the illumination light for observation and photography. The detection spot image can be irradiated at the most suitable position, making it possible to avoid photographing with the eyelids lowered.

[Brief explanation of the drawing]

The drawings show an embodiment of an ophthalmological instrument equipped with a pupil position detection function according to the present invention, and Fig. 1 shows its optical layout, and Fig. 2 shows the fundus illumination light and eyelid detection spot on the iris of the subject's eye. A front view showing the relative position to the image, Fig. 3 is a front view showing the state where the projection point of the spot image on the iris is covered by the eyelid, and Fig. 4 shows the state of the eyelid detection spot image on the light receiving element. Figure 5 is an explanatory diagram of the wavelength ranges used by the fundus illumination light and the eyelid detection light source, respectively. Figures 6 and 7 are diagrams showing the difference in output depending on the presence or absence of eyelids. FIG. 2 is a layout diagram according to an embodiment. 1 is an observation light source, 3 is an infrared transmission filter, 4 is a photography light source, 7 is a ring slit plate, 11 is an objective lens, 14 is a flip-up mirror, 16 is a photography film, 20 is an imaging tube,
21 is a light source for eyelid detection, 22 is a projection lens, 23 is a light receiving element, 25 is a mask, 26 is a light receiving lens, 27 is a beam splitter, E is the eye to be examined, El is the iris, El is the eyelid, and P2 is the eyelid detection spot image. , P2' are reflected spot images. Patent applicant: Canon Co., Ltd. Figure 2 Figure 3 Figure 4 Figure 5@-1)1

Claims (1)

[Scope of Claims] 1. In addition to an optical system for irradiating the eye to be examined for observation and photographing, there is also a means for projecting a light beam for eyelid detection onto the eye to be examined, and the light beam is directed to the iris of the eye to be examined or the iris of the eye to be examined. The pupil position detection function is characterized by detecting whether or not the eyelid is within the range required for ophthalmological examination by guiding reflected light from nearby to a photoelectric conversion means and measuring the reflected light. Equipped with ophthalmological instruments. 2. Equipped with a pupil position detection function according to claim 1, in which a reflected image of the eyelid detection light beam is guided to a photoelectric conversion means through an objective lens of an optical system for observing and photographing the eye to be examined. ophthalmological instruments. 3. Claim t in which the wavelength range of the eyelid detection light beam is different from the wavelength range used in the observation/photographing optical system.
An ophthalmological instrument equipped with a pupil position detection function according to item 51.