JPH01212536A - Eye inspection device - Google Patents

Abstract

PURPOSE:To simplify the structure and to reduce the cost by providing a plural focus optical system for imaging a plurality of object faces located at different distances simultaneously onto a same focal plane and a means for illuminating a plurality of object faces selectively. CONSTITUTION:When an eye E to be inspected is aligned with the optical system in an eyegrounds camera, a front eye illumination lamp 30 is lighted with a movable mirror 22 being located at a solid line position then the front eye section close to the cornea Ec is illuminated by infrared light and photographed with an infrared TV camera 27 through an objective lens 19, central hole and mirror section of a holed mirror 18, a focus lens 20, the short focus image section 21b of a double focus frenel lens 21, the movable mirror 22, a condenser lens 25 and a photograph lens 26. Then the front eye section is displayed on a monitor television 29. When the eyeground is viewed, a view light source 11 is lighted to illuminate the eyeground E with infrared light, and the light reflected at the eyeground Ef passes through same path as that in case of the front dye section observation thus displaying the eyeground Ef on the monitor television 29.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an ophthalmological examination instrument, such as a fundus camera, which has both an optical system for alignment and an optical system for examination.

[Prior Art] Conventionally, as this type of ophthalmological examination instrument, for example, the
The one disclosed in Japanese Patent No. 1-90 is known. FIGS. 5 and 6 show two aspects of this conventional example, one at the time of alignment and the other at the time of inspection. That is, in order to observe the anterior segment of the eye E to be examined for alignment, the auxiliary lens 1 is inserted on the observation optical axis as shown in FIG. The anterior segment of the eye is illuminated exclusively by light from the anterior segment illumination lamp 4.

When observing the fundus Ef of the eye E, the auxiliary lens l mentioned above is retracted from the observation optical axis as shown in FIG. The fundus Ef is illuminated exclusively with light from the fundus observation light source 2, while the light from the fundus observation light source 2 is prevented from entering the anterior segment of the eye. In addition, in FIGS. 5 and 6, 5 is a light source for photographing the fundus, 6 is an objective lens, 7 is a perforated mirror,
8 is a focusing lens, 9 is an infrared television camera, 10 is a photosensitive film, and 11.12 is an infrared filter.

[Problems to be Solved by the Invention] However, in the conventional example, when switching the observation region, it is necessary to bring out at least the auxiliary lens 1 on the observation optical axis and move it by λ, resulting in the following drawbacks.

(1) A guide mechanism, an operating section, or a driving means for taking the auxiliary lens 1 in and out is required.

(2) A switch is required to detect the position of the auxiliary lens 1.

(3) Due to the switching operation, the alignment state may shift when using manual drive, and operation noise may occur when using electric drive.

(Adjusting the position of the auxiliary lens l on the zero observation optical axis is complicated and difficult.

[Object of the invention] The object of the present invention is to improve the drawbacks of the above-mentioned conventional example,
An object of the present invention is to provide an ophthalmologic examination instrument that can switch and observe a plurality of locations at different positions in the optical axis direction by using a multifocal optical system and illumination means that can accommodate a plurality of observation locations.

[Summary of the Invention] The gist of the present invention for achieving the above-mentioned object is to provide a multifocal optical system that simultaneously images a plurality of object planes located at different distances on the same imaging plane, and and illumination means for selectively illuminating. This is an ophthalmological examination instrument characterized by the following.

[Embodiments of the Invention] The present invention will be described in detail based on the embodiments illustrated in FIGS. 1 to 4.
Explain.

FIG. 1 shows an embodiment in which the present invention is applied to a non-mydriatic fundus camera. In No. 17, 11 is a light source for observation, and along this optical path there is an infrared filter 12, a condenser lens 131, . A photography light source 14, a condenser lens 15, a ring slit plate 16 having an annular aperture, a relay lens 17, and a perforated mirror 18 are arranged in sequence, and an objective lens 19 is placed between the perforated mirror 18 and the eye E to be examined. It is located. Of these, observation light source 11, photography light source 1
4, ring slit plate 16, perforated mirror 18 and cornea E
c is substantially conjugate with the condenser lens 13, condenser lens 15, relay lens 17, and objective lens 19, respectively.

Furthermore, as shown by curve A in FIG. 3, the infrared filter 12 does not transmit visible light that would cause miosis of the subject's eye E due to the emission spectrum of the observation light source 11, The television camera has a characteristic of transmitting relatively shorter wavelengths of infrared light in the sensitivity wavelength range of curve B shown in FIG. 3. A portion of the perforated mirror 18 has the characteristics of reflecting the light transmitted by the infrared filter 12 and visible light with shorter wavelengths, and transmitting light in the wavelength range of the infrared filter 31, which will be described later. are doing.

In front and behind the perforated mirror 18, there are a single focusing lens 20 movable in the optical axis direction, and a bifocal Fresnel lens 21 as an example of a multifocal optical system that accommodates a plurality of focal lengths. Observation □ Movable mirror 22 that switches between the optical path and the photographing optical path. A shutter 23 that opens an optical path during photographing and a photographic film 24 are arranged in this order. In addition, the bifocal Fresnel lens 21
As shown in an enlarged view in FIG. 2, it has a long focal length imaging section 21a and a short focal length imaging section 21b, each having a small band annular shape, for example.

Further, on the reflection side of the movable mirror 22, there is a condenser lens 25 and an imaging lens 26, which are disposed at a position substantially co-located with the film 24 with respect to the movable mirror 22, and are sensitive to the infrared light region and have an imaging surface. An infrared camera 27 is placed approximately conjugate to the film 24, and the infrared light imaging signal from the infrared television camera 27 is sent to a monitor television 29 via a cable 28 to be displayed on a cathode ray tube as visualization display means. It is designed to be projected on the surface 29a. Note that e represents the examiner's eye for observing this.

In addition, diagonally in front of the subject's eye E, there is an anterior segment illumination lamp 30 for illuminating the anterior segment of the subject's eye when necessary, which overlaps with the infrared television sensitivity area as shown in FIG. 3B. An infrared filter 31 that transmits wavelength C in a longer wavelength range than the outer filter 12. A light blocking means 32 is arranged to block external light entering the anterior segment of the eye.

In FIG. 1, Pl and P2 indicate the imaging positions of the fundus Ef and the cornea Ec by the objective lens 19, respectively, and the fundus Ef is a film with respect to the long focus imaging section 21a of the P11 focusing lens 20 and the bifocal Fresnel lens 21. It is said to be approximately conjugate with 24.

Next, to explain the operation of this embodiment, during alignment to establish a proper relationship between the optical system of the eye E and the fundus camera body, the anterior segment illumination lamp 30 is turned on with the movable mirror 22 at the position indicated by the solid line. Then, the cornea Ec of the eye E to be examined is
The anterior segment of the eye in the vicinity of Focus imaging unit 21b, movable mirror 22, condenser lens 25. The image is taken by an infrared television camera 27 through an imaging lens 26, and the anterior segment of the eye is displayed on a monitor television 29. The examiner can operate the fundus camera while observing this image.

When observing the fundus, if the anterior ocular segment illumination lamp 30 is turned off and the observation light source 11 is turned on, the infrared light for fundus observation that has passed through the infrared filter 12 is transferred to a hollow, transparent photographing device by the condenser lens 13. The light is focused near the light source 14, near the ring slit plate 16 by the condenser lens 15, and near the perforated mirror 18 by the relay lens 17, reflected by the mirror surface of the perforated mirror 18, and travels to the left. After the object lens 19 forms an image in the vicinity of the cornea Ec in the shape of a slit of the ring slit plate 16, the fundus Ef is irradiated. The light reflected by the fundus Ef and traveling to the right is once imaged at the position Pl by the objective lens 19, and then passes through the central hole of the perforated mirror 18, the focusing lens 20, and the long focal point of the bifocal Fresnel lens 21. The light passes through the imaging section 21a and is then projected onto the monitor television 29 through the same optical path as in the case of anterior eye segment observation. The examiner observes this image and selects the area to be imaged and performs focusing operations.

When photographing the fundus, the movable mirror 22 is moved up to the dotted line position, the shutter 23 is opened, and the photographic light source 14 is momentarily emitted, so that the light beam passes through the same optical path as when observing the fundus and illuminates the fundus Ef. The reflected light reaches the film 24, and the fundus Ef can be photographed. Therefore, when switching between observing the anterior segment of the eye and observing the fundus of the eye, there is no need to insert or remove the auxiliary lens into the optical path of the imaging optical system as in the conventional example.

The long focus imaging section 21a and the short focus imaging section 21b of the bifocal Fresnel lens 21 are not necessarily arranged in an annular shape, but may be arranged in a checkered pattern, for example, or have different refractive powers. It is also possible to split the part into two sides. It is also possible to have multiple focal points of three or more.

Furthermore, as in the second embodiment shown in FIG. 4, a normal spherical lens 33 is placed in a position that also serves as a photographic lens, and a bifocal Fresnel lens, which is a multifocal optical system, is placed in the optical path used only for observation. 34 may be placed in place of the imaging lens 26 in FIG. It is possible to eliminate such inconveniences.

Although the above-described embodiments show the case where the present invention is applied to a non-mydriatic fundus camera, the present invention can also be applied to various other ophthalmological instruments that use both an optical system for alignment and an optical system for an ophthalmological examiner. Of course.

[Effects of the Invention] As explained above, the ophthalmological examination instrument according to the present invention includes a multi-focal optical system that simultaneously images a plurality of object planes located at different distances on the same imaging plane, and selects the plurality of object planes. By using an illumination means for illuminating, there is no need to take the optical system in and out of the optical path when switching objects as in the conventional example. Therefore, the mechanism for putting in and taking out the optical system can be omitted, simplifying the mechanism and reducing manufacturing costs. This is advantageous in reducing the

Further, since the space required for retracting the optical system is not required, there are also effects such as making the device smaller and lighter and increasing the degree of freedom in the arrangement position. Furthermore, there is an advantage that the switching operation can be performed more quickly than, for example, a method in which the focusing lens is largely moved along the optical path or the machine is moved largely toward or away from the eye to be examined.

[Brief explanation of the drawing]

Drawings 1 to 4 show an embodiment of an ophthalmological examination instrument according to the present invention, FIG. 1 is a layout diagram of an embodiment applied to a fundus camera, and FIG. 2 is a sectional view of a bifocal Fresnel lens. FIG. 3 is a graph of wavelength characteristics, FIG. 4 is a layout diagram of another embodiment, and FIGS. 5 and 6 are layout diagrams of a conventional example. Reference numeral 11 is an observation light source, 12.31 is an infrared filter, 1
4 is a light source for photography, 16 is a ring slit plate, 18 is a perforated mirror, 19 is an objective lens, 20 is a focusing lens, 21%
34 is a bifocal Fresnel lens, 21a is a spherical lens,
22 is a movable mirror, 23 is a shutter, 24 is a film,
26 is an imaging lens, 27 is an infrared television camera, 29 is a monitor television, 30 is an anterior segment illumination lamp, 32 is a light shielding means, and 33 is a spherical lens. Figure 3/Figure 5 Figure 4'61

Claims (1)

[Claims] 1. A multi-focal optical system that simultaneously images a plurality of object planes located at different distances on the same imaging plane, and an illumination means that selectively illuminates the plurality of object planes. An ophthalmological examination instrument featuring: 2. The ophthalmological examination according to claim 1, wherein the long focus imaging section of the multifocal optical system images the fundus, and the short focus imaging section images the anterior segment of the eye on the imaging plane. instrument.