JPH03136633A - Ophthalmic lighting device - Google Patents

Abstract

PURPOSE:To obtain a sufficient brightness in the front eye part and regularly keep the light reached to the retina minimum by forming a zonal lighting light flux by use of the characteristic of a light guide, and making its radial light intensity distribution adjustable to adjust the illuminating light quantity to the pupil. CONSTITUTION:When a light is entered to an end surface of incidence 8a at an incident angle of theta by use of a light guide 8 consisting of single or plural number of optical fibers as a lighting system, the light is radiated in a conical form having a top angle 2theta from a radiation end surface 8b to form a wide zonal illumination. When the angle of incidence is reduced, the diameter of the zonal illumination is reduced to form an uniform illumination having a small diameter near theta=0 deg.. Thus, when the angle of incidence and the area of a shielding member are changed to change the light quantity near the axis of the light guide, the axially radiated light quantity is largely changed, compared with the angle direction separated from the axial direction. When the radiated light is projected to the front eye part, and the part capable of adjusting the light quantity is fitted to the pupil to utilize this luminous intensity distribution characteristic of the light guide, the light quantity reached to the retina can be adjusted, and the purpose can be attained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an ophthalmic illumination device that is effective in illuminating the anterior segment of the eye with strong light for a long period of time.

[Conventional technology]

In an ophthalmological lighting device that has strong illumination light, the illumination light may cause damage to the patient's eyes. In order to reduce the burden on patients, for example,
As described in Japanese Patent No. 11625, an apparatus has been proposed that weakens only the light in the pupil of the eye to be examined.

As shown in FIG. 9, this consists of a lamp l, a condensing lens 2, and a light-shielding/dimmer member such as an illumination area diaphragm that has a light absorption layer 3a in the center and can be inserted into and removed from the optical path. 3, reflective members 4 and 5 such as prisms, and an objective lens 6 for observation.
Annular illumination is performed with the central part of the pupil 7a of the eye 7 to be examined shaded through the eye, and fundus illumination is performed.

It should be noted that the light shielding/light attenuating member 3
It is inserted at a conjugate position with.

[Problem to be solved by the invention]

However, since the light shielding/light reduction member 3 in the conventional example described above generally cannot adjust the transmittance, the brightness may be inappropriate when viewing near the pupil. Furthermore, although it is easier to observe if the light shielding/light reduction member 3 is removed, strong illumination light enters the eye, which is likely to cause damage to the fundus of the eye.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, an object of the present invention is to provide an ophthalmic illumination device that can provide sufficient brightness to the anterior segment of the eye and can be adjusted to always keep the light reaching the retina at a minimum. .

[Means and effects for solving the problems] An ophthalmic illumination device according to the present invention includes an illumination light source, a condensing optical system that converges the illumination light emitted from the illumination light source, and a condensing optical system that converges the illumination light emitted from the illumination light source. A light guide made of one or more optical fibers that receives a light beam at an entrance end face and transmits it to an exit end face, and an illumination optical system that guides the light emitted from the exit end face of the light guide to the anterior segment of the eye to be examined. , by making variable the angle of incidence of the central ray of the light beam incident on the light guide with respect to the incident end surface in the meridian plane including the axis of the light guide, the characteristics of the light guide are utilized to create an annular illumination light beam; The radial light intensity distribution is adjustable so that the amount of light irradiated to the pupil can be adjusted;
This allows the amount of light reaching the retina to be adjusted.

That is, in order to achieve the above object, the ophthalmic illumination device according to the present invention uses a light guide made of one or more optical fibers in the illumination system.

As shown in FIG. 1, the light guide 8 emits light at an incident angle θ (the angle of incidence of the central ray of the light beam entering the light guide 8 on the incident end surface 8a in the meridian plane including the axis of the light guide 8). When the light is made incident on the entrance end face 8a, annular illumination with a conical width and an apex angle of 2θ is produced from the exit end face 8b. As the incident angle θ is decreased, the diameter of the annular illumination becomes smaller, and when θ=0°, the illumination ceases to be an annular illumination and becomes uniform illumination with a small illumination field diameter. Therefore, if you change the incident angle θ or change the area of the light shielding member so as to change the amount of light near the axis of the light guide 8, the amount of light emitted in the axial direction of the light guide 8 will change in the axial direction of the light guide 8. It changes greatly compared to the angular direction away from . In order to utilize the light distribution characteristics of the emitted light from the light guide 8, the emitted light is projected onto the anterior segment of the eye, and by aligning the part where the light amount can be adjusted with the pupil, the amount of light reaching the retina can also be adjusted. Thus, the above objective is achieved.

The central ray of the incident luminous flux is changed when the radial intensity distribution of the luminous flux that illuminates the anterior segment of the subject's eye is changed by blocking the central part of the incident luminous flux with a liquid crystal or the like and changing the luminous flux width of the peripheral luminous flux. refers to the annular ray at the center of the outer circle and inner circle of the annular incident light beam.

〔Example〕

Hereinafter, the present invention will be described in detail based on the illustrated embodiment, with the same reference numerals assigned to the same members as in the above-mentioned conventional example.

FIGS. 2 and 3 show optical systems on the incident side and exit side of the light guide of the first embodiment of the ophthalmic illumination device according to the present invention, respectively.

In FIG. 2, the input optical system consisting of the lamp 1 and the condensing lens 2 has a rotation axis near the input end face 8a of the light guide 8, and the entire input optical system can be rotated around this axis. It looks like this.

In FIG. 3, reference numeral 9 denotes a condensing lens disposed between the exit end surface 8a of the light guide 8 and the reflecting member 4, and the condensing lens 9, the reflecting member 4.5, and the objective lens 6 are connected to each other on the exit side. It makes up the optical system. Note that 10 is a lens system that together with the objective lens 6 constitutes an observation system.

Since this embodiment is configured as described above, if the axial direction of the light guide 8 and the optical axis of the input optical system match,
The light distribution on the exit side is uniform. Furthermore, when the optical axis of the input optical system is rotated around the rotation axis until no light enters in the axial direction of the light guide 8, the direction parallel to the axial direction of the light guide 8 (hereinafter referred to as the exit side main (referred to as the ray direction) becomes 0. In the middle of these conditions, the light intensity ratio between the exit-side principal ray direction and the peripheral direction changes from 0 to 1.

In addition to the above configuration, the light guide 8 may be rotated on the meridional surface around the incident end surface 8a of the light guide 8,
As shown in FIG. 4, a similar effect can be obtained by moving the slider 11 with a suitable hole in a direction perpendicular to the axial direction of the light guide 8.

Here, the intensity of the light beam emitted from the light guide 8 is determined by the angle it makes with the axial direction of the light guide 8 on the exit side. In order to reflect this exit light (illumination light) characteristic on the anterior segment of the eye 7, it is necessary to image the exit side principal ray on the anterior eye segment, and for this purpose, the exit side optical system (the exit light When passing through the objective lens 6, it is necessary to focus the rear side (including the objective lens 7) on the anterior segment of the eye. Thereby, the amount of light near the pupil 7a can be adjusted while observing the anterior segment of the eye with the observation system, and the amount of light reaching the retina can be minimized.

Further, the portion where the intensity of the emitted light (illumination light) can be changed is determined by the normal direction of the emitting end surface 8b of the light guide 8. Therefore, if the normal direction of the exit end surface 8a of the light guide 8 can be freely changed, the amount of light can be freely changed in any part of the field of view, and the field of view is not restricted. The dark part of the exit light (illumination light) can also be changed by adjusting the entrance optical system, so it is possible to make the dark part match the pupil diameter, or to adjust the dark part so that strong illumination light does not enter the pupil even if the focus is removed from the pupil. The diameter of the part can also be increased, improving operability.

FIG. 5 shows the entrance-side optical system of the second embodiment, in which a light-shielding plate 12 is placed between the entrance end face 8a of the light guide 8 and the lamp 1, which can provide annular illumination and whose diameter can be changed. . It is preferable that this light shielding plate 12 be placed as far as possible from a position conjugate with the incident end surface 8a of the light guide 8, and ideally, it should be placed at a position corresponding to the aperture stop of the incident optical system. Moreover, even when the diameter of the light shielding plate 12 is the minimum, the light guide 8
The incident end surface 8a of the light guide 8 is cut diagonally so that the intensity characteristics of the emitted light depending on the angle are constant.

Since this embodiment is configured as described above, the light shielding plate 12
As the diameter of the light guide increases, only the light intensity in the direction of the exit side principal ray decreases, and when light no longer comes from the light guide axis direction,
The amount of light in the direction of the exit-side principal ray becomes 0. At this time, there is no change in the amount of light in the direction where the exit angle is large.

Incidentally, if an annular opening is made using an electrochromic element 12' or a liquid crystal element as shown in FIG. 6 instead of the light shielding plate 12 whose diameter can be changed, the inner diameter can be reduced to zero, and the inner diameter can be reduced to zero. As a result, there is no need to obliquely cut the incident end face 8a of the light guide 8, and the structure can be simplified.

FIG. 7 shows the entrance side optical system of the third embodiment, which uses an elliptical concave mirror 13, with a lamp l at the focal point on the reflecting surface side and an entrance end surface 8a of the light guide 8 at the other focal point. The equipment was there. As shown in FIG. 8, the light that hits the lamp l after being reflected by the elliptical concave mirror 13 is blocked, so that the light near the optical axis becomes weaker. When this light is made incident on the incident end face 8a of the light guide 8, the light distribution on the exit side will be the same. In order to make this -like illumination, the light guide 8
The incident end surface 8a of the 100 mm is cut diagonally. This cut refracts the light beam at the incident surface 8a, so that the light beam passes in the direction of the light guide axis, and the light distribution on the exit side becomes uniform. In order to be able to adjust the light amount in the light guide axis direction, the light guide axis and the input optical system axis should not be aligned.
The incident end surface 8a of the light guide 8 is cut diagonally so that the light guide 8 can be rotated using the light guide axis as the rotation axis. Through this rotation, the direction of the optical axis of the input optical system after entering the light guide matches the direction of the light guide axis, and the dark part of the input optical system matches the direction of the light guide axis after entering the light guide 8. The angle between the light guide axis and the optical axis of the input optical system and the cut angle of the input end surface are determined so that the light guide axis and the optical axis of the input optical system can be in a state in which the light guide axis is not exposed. light guide 8
By rotating the incident end surface 8a, only the intensity near the principal ray of the exit side optical system changes, and the desired light distribution can be obtained.

This is because the light distribution on the incident side of the light guide 8 is changed three-dimensionally.

Incidentally, as the incident side optical system, the incident optical system shown in FIG. 5 in which the diaphragm 12 is fixed may be used, and the same effect can be obtained in that case as well.

〔Effect of the invention〕

As described above, the ophthalmic illumination device according to the present invention provides highly safe illumination that has sufficient brightness for the anterior segment of the eye and can be adjusted so that the minimum necessary amount of light always enters the fundus. This has important practical advantages.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the light distribution characteristics of the emitted light of the light guide used in the present invention, and FIG. 2 and FIG. FIG. 4 is a diagram showing a modification of the entrance side optical system of the first embodiment, FIG. 5 is a diagram showing the entrance side optical system of the second embodiment,
Fig. 6 is a diagram showing a modification of the aperture in the second embodiment, Fig. 7 is a diagram showing the entrance side optical system of the third embodiment, and Fig. 8 is a diagram showing a modification of the aperture in the third embodiment. Diagram showing the principle of
The figure shows a conventional optical system. 1... Lamp, 2, 9... Condensing lens, 4, 5
... Reflection member, 6 ... Objective lens, 7 ...
Eye to be examined, 7a...pupil, 8...light guide,
8a...Incidence end face, 8b...Emission end face, lO.
...Lens system, 11...Slider, 12...
Light shielding plate, 12'...Figure 2 Figure 3 Figure 7 Figure 9

Claims (1)

[Claims] An illumination light source, a condensing optical system that converges the illumination light emitted from the illumination light source, and one or more optical fibers that receive the light beam focused by the condensing optical system at an incident end face and transmit it to an exit end face. and an illumination optical system that guides the light emitted from the exit end surface of the light guide to the anterior segment of the subject's eye, the center of the light beam incident on the light guide in the meridian plane including the axis of the light guide. An ophthalmological illumination device in which the angle of incidence of a light beam with respect to the incident end surface is variable.