JP7645684B2 - Illumination light source and ophthalmic device - Google Patents

Description

The present invention relates to an illumination light source used in an ophthalmic device, and an ophthalmic device equipped with this illumination light source.

Fundus cameras (ophthalmic devices) that photograph the fundus of a subject's eye are well known (see Patent Documents 1 and 2). These fundus cameras are equipped with an illumination system that irradiates the fundus of the subject's eye with various types of illumination light, and a light receiving system that images (detects, receives) the return light from the illumination area of the illumination light irradiated onto the fundus. The return light is light that returns from the illumination area of the fundus or an area nearby, and includes reflected light of the illumination light, scattered light of the illumination light, and fluorescence excited by the illumination light and its scattered light.

The illumination system of such a fundus camera is provided with a diaphragm (but not limited to this) that is optically conjugate or nearly conjugate with the cornea, iris, and posterior surface of the crystalline lens of the subject eye. The diaphragm has, for example, a ring-shaped opening, and prevents the reflected light of the illumination light that is reflected or scattered by the cornea, crystalline lens, etc. of the anterior part of the subject eye from entering the light receiving system (see Patent Document 2). This prevents noise light (flare, ghost, etc.) caused by reflection and scattering by the cornea, crystalline lens, etc. from being mixed into the captured image.

Patent No. 5735211 JP 2018-110691 A

Figure 11 is an explanatory diagram for explaining the problems with a conventional illumination system. Note that Figure 11 shows a simplified illumination system that has an illumination light source 300, an aperture 302, and an optical system (not shown), and irradiates illumination light L0 onto the fundus Ef through the anterior segment Ea of the subject's eye E.

As shown in FIG. 11, when the illumination light L0 emitted from the illumination light source 300 enters the aperture 302, a part of the illumination light L0 passes through the ring-shaped opening 302a formed in the aperture 24, but the illumination light L0 that does not pass through this opening 302a is blocked by the light-shielding portion 302b of the aperture 302. For this reason, a part of the illumination light L0 emitted from the vicinity of the central axis CA (illumination optical axis) of the illumination light source 300 is blocked by the light-shielding portion 302b and is not used to illuminate the fundus Ef. As a result, in order to ensure the necessary amount of illumination light L0 irradiated to the fundus Ef, it is necessary to increase the amount of illumination light L0 emitted from the illumination light source 300, which increases power consumption. Alternatively, if the illumination light source 300 does not have sufficient brightness, the effective amount of illumination light is reduced. The imaging time is extended, which increases the burden on the subject, and the possibility of imaging failure due to the influence of fixational micromovement of the subject's eye E increases.

The present invention has been made in consideration of these circumstances, and aims to provide an illumination light source and an ophthalmic device that can efficiently illuminate the subject's eye.

The illumination light source for achieving the object of the present invention is an illumination light source of an ophthalmic device that irradiates illumination light to a subject's eye, and is provided with a light-emitting section that emits illumination light, a cover that covers the light-emitting section, and one or more light-transmitting sections that are provided in the cover at a position eccentric from the central axis of the illumination light source, and the cover emits illumination light only from the light-transmitting sections.

In another aspect of the present invention, in an illumination light source, at least a portion of the area of the outer or inner surface of the cover that is different from the translucent portion is a reflective surface.

In another aspect of the illumination light source of the present invention, the light-transmitting portion is formed into a pair of slits that are perpendicular and symmetrical with respect to the central axis.

In another aspect of the illumination light source of the present invention, the light-transmitting portion is formed in a ring shape centered on the central axis.

To achieve the object of the present invention, an ophthalmic device is provided with the above-mentioned illumination light source.

An ophthalmic device according to another aspect of the present invention is provided with a diaphragm having a ring-shaped opening through which illumination light emitted from an illumination light source passes.

The present invention can efficiently illuminate the subject's eye.

FIG. 1 is a schematic diagram of a fundus camera. FIG. FIG. 2 is a front view of the illumination light source as viewed from the aperture stop side. 4 is a cross-sectional view of the illumination light source taken along line 4-4 in FIG. 3. 4 is a cross-sectional view of the illumination light source taken along line 4-4 in FIG. 3. 13A and 13B are explanatory diagrams showing modified examples of the shape of the light-transmitting portion. 13A and 13B are explanatory diagrams showing modified examples of the light-emitting unit. FIG. 1 is a schematic diagram showing an example of a normal fundus camera (including a multifunction device) that does not perform slit scan photography. FIG. 9 is a front view of the aperture of the fundus camera shown in FIG. 8 . FIG. 9 is an explanatory diagram showing an example of an illumination light source of the fundus camera shown in FIG. 8 . 1 is an explanatory diagram for explaining a problem with a conventional illumination system.

[Overall configuration of fundus camera]
Fig. 1 is a schematic diagram of a fundus camera 10 corresponding to the ophthalmologic apparatus of the present invention. As shown in Fig. 1, the fundus camera 10 photographs the fundus Ef of the subject's eye E by a slit scan method (hereinafter, abbreviated as slit scan photography), and includes an illumination system 20, an optical scanner 30, and a light receiving system 40.

The illumination system 20 irradiates a portion of the fundus Ef with illumination light LS (slit light) via an optical scanner 30 described below. This illumination system 20 includes an illumination light source 22, an aperture 24, a slit aperture 26, an illumination system lens 28, a lens 31, an optical path splitting member 34, and an objective lens 38. The aperture 24, the optical scanner 30, the optical path splitting member 34, and the anterior segment Ea of the subject's eye E are in an optically conjugate relationship.

The illumination light source 22 emits illumination light L. Visible light is used as this illumination light L, but infrared light, which is light in the infrared region (including the near-infrared region) to which the subject's eye E has low sensitivity, may also be used. The illumination light source 22 may be, but is not limited to, a laser light source, an LED (Light Emitting Diode) light source, a white LED light source, a laser-excited white light source, or the like.

2 is a front view of the aperture 24. As shown in FIG. 2 and FIG. 1, the aperture 24 includes, but is not limited to, an aperture (such as an iris aperture or an anterior lens aperture) that is optically conjugate or nearly optically conjugate with the cornea, iris, or posterior lens of the subject's eye E. The aperture 24 is a light-shielding member having a pair of openings 24a that are perpendicular and symmetrical to the illumination optical axis OB (the central axis CA of the illumination light source 22 described later, see FIG. 4), which is the optical axis from the illumination light source 22 of the illumination system 20 to the illumination system lens 28, and prevents the reflected light of the illumination light LS described later reflected by the anterior eye segment Ea (anterior lens) from entering the light-receiving system 40. The illumination light L that passes through the aperture 24 enters the slit aperture diaphragm 26. The symbol 24b is a light-shielding portion located inside the opening 24a (on the illumination optical axis OB side). Although not shown in FIG. 2, depending on the width of the light-shielding portion 24b, a holding member for holding the light-shielding portion 24b may be provided in the opening 24a portion.

The slit aperture diaphragm 26 generates illumination light LS from the illumination light L incident from the diaphragm 24, and emits this illumination light LS toward the illumination system lens 28. When focused, the illumination light LS becomes a slit shape (slit light) parallel to the X direction at the fundus position and the fundus conjugate position. Note that the illumination light LS (slit light) is not particularly limited as long as it is perpendicular to the optical axis of the objective lens 38 (illumination system 20). In addition, the slit aperture diaphragm 26 is provided so as to be freely movable along the optical path of the illumination light LS by an actuator (not shown). By moving this slit aperture diaphragm 26, the illumination system 20 can be focused on the fundus Ef.

The illumination system lens 28 emits the illumination light LS incident from the slit aperture stop 26 toward the optical scanner 30. The optical path splitting material 34 and the objective lens 38 will be described later. The lens 31 emits the illumination light LS reflected by the optical scanner 30 toward the optical path splitting material 34. The lens 31 makes the optical scanner 30 and the optical path splitting material 34 optically conjugate with each other. The optical path splitting material 34 and the objective lens 38 will be described later.

The illumination system 20 may be a projector capable of emitting illumination light LS. Examples of such projectors include LCD projectors, LCOS (Liquid crystal on silicon) projectors using a reflective liquid crystal panel, and projectors using a DMD (Digital Mirror Device). In this case, the optical scanner 30 may be replaced by a fixed mirror, and the optical scanning performed by the optical scanner 30 may be simulated by changing the pattern of the projector.

The optical scanner 30 is a deflection mechanism capable of one-dimensionally deflecting (scanning) the illumination light LS, such as a galvanometer mirror, a resonant mirror, a polygon mirror, or a MEMS (Micro Electro Mechanical Systems), and is disposed at the intersection of the optical axis of the illumination system lens 28 and the optical axis of the lens 31. This optical scanner 30 reflects the illumination light LS incident from the illumination system lens 28 toward the lens 31, and deflects the illumination light LS during slit scan photography.

The optical path splitting material 34 reflects the illumination light LS incident from the lens 31 and emits it toward the objective lens 38, and also passes the return light LB incident from the objective lens 38, which will be described later, and emits it toward the focus optical system 36. Note that various splitters can be used as the optical path splitting material 34 as long as it is capable of splitting the illumination light LS and the return light LB, reflecting the illumination light LS toward the objective lens 38, and emitting the return light LB toward the focus optical system 36.

The objective lens 38 irradiates the illumination light LS reflected by the optical path splitting material 34 onto a part of the fundus Ef through the anterior segment Ea (pupil) of the subject's eye E. At this time, the illumination light LS is deflected by the optical scanner 30 described above, so that the illumination light LS scans the fundus Ef. While the illumination light LS is being deflected, return light LB from the fundus Ef of the subject's eye E irradiated with the illumination light LS enters the focus optical system 36 through the objective lens 38 and the optical path splitting material 34.

The light receiving system 40 includes an objective lens 38, an optical path splitter 34, a focusing optical system 36, a light receiving system lens 42, and a CMOS type image sensor 44.

The focus optical system 36 includes one or more lenses (focus lenses) that can move along the optical path of the return light LB, and adjusts the focus of the fundus camera 10 (light-receiving system 40) under the control of the control device 18. The focusing of the light-receiving system 40 by the focus optical system 36 and the focusing of the illumination system 20 by the slit aperture diaphragm 26 move in conjunction with each other according to the diopter (visual acuity) of the subject's eye E. The return light LB that enters the focus optical system 36 from the optical path splitter 34 enters the light-receiving system lens 42. Note that instead of providing one or more movable focus lenses in the focus optical system 36, one or more variable focus lenses may be provided, and the method of focus adjustment is not particularly limited.

The light receiving lens 42 is composed of one or more lenses, and focuses the return light LB incident from the focus optical system 36 onto the image sensor 44.

The image sensor 44 has a light receiving surface 44a on which the return light LB from the light receiving lens 42 is incident, and has a rolling shutter function that captures (receives) the return light LB while shifting the timing of the start and end of exposure for each area (including each pixel and each line) within this light receiving surface 44a (see Patent Document 1). During slit scan photography, this image sensor 44 is driven by the rolling shutter to capture the return light LB of the illumination light LS that moves within the fundus Ef in response to the deflection of the illumination light LS by the optical scanner 30.

[Configuration of illumination light source]
Fig. 3 is a front view of the illumination light source 22 as viewed from the diaphragm 24 side. Fig. 4 is a cross-sectional view taken along line 4-4 of the illumination light source 22 in Fig. 3. Fig. 5 is a cross-sectional view taken along line 4-4 of the illumination light source 22 in Fig. 3, with the cover 104 in Fig. 4 omitted to avoid complication of the drawing. As shown in Figs. 3 to 5, the illumination light source 22 includes a central axis CA coinciding with the illumination optical axis OB, a light-emitting unit 100, a lead wire 102, and a cover 104.

The light-emitting unit 100 is a white LED, and includes an excitation light source 100a made of an LED, a base 100b on which the excitation light source 100a is provided, and a light conversion material 100c containing a phosphor. The excitation light source 100a is connected to a lead wire 102 via a bond wire BW, and emits excitation light (e.g., blue light) upon receiving power from the lead wire 102.

The base 100b has a holding hole that holds the excitation light source 100a. The excitation light source 100a is covered by the light conversion material 100c inside the holding hole. The light conversion material 100c emits illumination light L, which is white light, by irradiating the excitation light from the excitation light source 100a and causing the phosphor to emit light (emit red and green light).

The cover 104 is solid and substantially dome-shaped, and covers the front side (the side from which the illumination light L is emitted) of the light-emitting unit 100. The inside of the cover 104 is filled with a transparent resin material 105 (see FIG. 4). The cover 104 may be hollow. The tip (upper end in FIG. 4) of the outer peripheral surface of the cover 104 is provided with a pair of slit-shaped light-transmitting sections 106 that are formed by an opening window 108a of a reflecting surface 108 described later and that can emit the illumination light L toward the front side (diaphragm 24 side) of the illumination light source 22. Each light-transmitting section 106 is formed at a position eccentric to the central axis CA at the tip of the cover 104. Specifically, each light-transmitting section 106 extends in a direction perpendicular to the central axis CA and is formed in a symmetrical slit shape with the central axis CA in between.

A reflective surface 108 capable of reflecting the illumination light L is formed on the outer surface of the cover 104. When the cover 104 is formed in a hollow shape, the reflective surface 108 may be formed on the inner surface of the cover 104. In addition, in FIG. 4, the thickness of the layer having the reflective surface 108 is exaggerated from the actual thickness in order to clarify the reflective surface 108. The reflective surface 108 is, for example, a mirror surface, and is formed on almost the entire surface of the outer surface of the cover 104 in an area different from the translucent portion 106, and totally reflects light in the wavelength range of the illumination light L. An opening window 108a that exposes the translucent portion 106 is formed on the reflective surface 108. Therefore, the illumination light L that does not enter the translucent portion 106 among the illumination light L emitted from the light emitting portion 100 is reflected on the reflective surface 108 and is repeatedly reflected and scattered on the surfaces of the light conversion material 100c and the excitation light source 100a, and is emitted from the area where the reflective surface 108 is not formed, i.e., the translucent portion 106. Therefore, in this embodiment, the illumination light L that does not directly enter the light-transmitting portion 106 from the light-emitting portion 100 can also be reused. This increases the brightness of the illumination light source 22 without increasing power consumption.

In this way, the illumination light source 22 of this embodiment can collect the illumination light L emitted from the light-emitting unit 100 at the light-transmitting unit 106 by the reflecting surface 108, and emit the illumination light L only from the light-transmitting unit 106. As a result, it is possible to reduce the amount of illumination light L blocked by the light-blocking unit 24b of the aperture 24 located on the central axis CA (illumination optical axis OB). This makes it possible to increase the amount of illumination light L that passes through the aperture 24 among the illumination light L emitted from the light-emitting unit 100, i.e., the amount of illumination light L used to illuminate the fundus Ef, and allows efficient illumination of the fundus Ef.

[others]
Fig. 6 is an explanatory diagram showing modified shapes of the light-transmitting portion 106. In the above embodiment (see Fig. 3), a part of the light-transmitting portion 106 is formed in a curved shape when the illumination light source 22 is viewed from the diaphragm 24 side, but the shape of the light-transmitting portion 106 may be changed as shown in Fig. 6, or may be changed to a shape other than those shown in Figs. 3 and 6. In addition, the number of light-transmitting portions 106 formed on the cover 104 may be changed to one or three or more.

Figure 7 is an explanatory diagram showing a modified example of the light-emitting unit 100. In the above embodiment, a white LED is used as the light-emitting unit 100, but any monochromatic LED 100d may be used. In this case, a monochromatic LED 100d is provided in the light-emitting unit 100 instead of the excitation light source 100a and the light conversion material 100c, and the light emitted from this monochromatic LED 100d becomes the illumination light L.

Figure 8 is a schematic diagram showing an example of a normal fundus camera 10A (including a multifunction device) that does not perform slit scan photography. Note that the configuration of the fundus camera 10A is not limited to the configuration shown in Figure 8.

The fundus camera 10A is provided with an illumination system 200 for illuminating the fundus Ef and a light receiving system 220 for observing and photographing the fundus Ef.

The illumination system 200 includes an illumination light source 201, a condenser lens 202, a xenon lamp 203, a condenser lens 204, exciter filters 205 and 206, an aperture 207, a mirror 208, a liquid crystal display 209, an aperture 210, a relay lens 211, a holed mirror 212, and an objective lens 213.

The light receiving system 220 includes an objective lens 213, an aperture mirror 212 (aperture 212a), an aperture 221, barrier filters 222, 223, a focusing lens 224, a fixed lens 225, a photographing lens 226, a quick return mirror 227 (rotation shaft 227a), a field lens 228, a switching mirror 229 (rotation shaft 229a), an eyepiece lens 230, a relay lens 231, a mirror 232, a relay lens 233, an imaging device 234 for capturing still images of the fundus Ef, and an imaging device 235 for capturing video of the fundus Ef.

Figure 9 is a front view of the diaphragm 207 of the fundus camera 10A shown in Figure 8. Figure 10 is an explanatory diagram showing an example of the illumination light source 201 of the fundus camera 10A shown in Figure 8. As shown in Figure 9, the diaphragm 207 has a ring-shaped opening 207a and a light-shielding portion 207b surrounded by this opening 207a, and has the same function as the diaphragm 24 of the above embodiment. Although not shown in Figure 9, a holding member for holding the light-shielding portion 207b may be provided within the opening 207a.

As shown in FIG. 10, the illumination light source 201 has basically the same configuration as the illumination light source 22 of the above embodiment, except that the light-transmitting portion 106 is formed in a ring shape centered on the central axis CA. In a fundus camera 10A equipped with such an illumination light source 201, the aperture 207 may be omitted (the same applies to the aperture 24 of the fundus camera 10 of the above embodiment).

In the above embodiment, the light-transmitting portion 106 is formed of a transparent resin material, but the light-transmitting portion 106 may be an opening (through hole). In the above embodiment, the cover 104 and the reflective surface 108 are formed separately, but the two may be integrated. In the above embodiment, the reflective surface 108 is formed on almost the entire area of the outer surface of the cover 104 (or the inner surface if the cover 104 is hollow) other than the light-transmitting portion 106, but the reflective surface 108 may be formed on at least a part of this area. Furthermore, the reflective surface 108 may be formed in front of the light-emitting portion 100 at a position that does not interfere with the emission of the illumination light L from the excitation light source 100a.

In the above embodiment, an example of the arrangement of the illumination system 20, the optical scanner 30, and the light receiving system 40 of the fundus camera 10 is shown in FIG. 1, but the arrangement of each of these parts can be changed as appropriate.

In each of the above embodiments, the illumination light source 22, 201 of the fundus camera 10, 10A has been described as an example, but the present invention may also be applied to an illumination light source 22 used in an ophthalmic device that observes other observed parts of the subject's eye E (e.g., the anterior segment Ea).

10 Fundus camera 20, 200 Illumination system 22, 201 Illumination light source 24, 207 Aperture 24a, 207a Aperture 24b, 207b Light shielding portion 26 Slit aperture diaphragm 28 Illumination system lens 30 Optical scanner 31 Lens 34 Optical path splitting material 36 Focus optical system 38 Objective lens 40, 220 Light receiving system 42 Light receiving system lens 44 Image pickup element 44a Light receiving surface 100 Light emitting portion 100a Excitation light source 100b Base 100c Transparent resin 100d Monochromatic LED
102 Lead wire 104 Cover 106 Light-transmitting portion 108 Reflecting surface 108a Opening window BW Bond wire CA Central axis E Eye to be inspected Ea Anterior segment Ef Fundus L Illumination light L0 Illumination light LB Return light LS Illumination light OB Illumination optical axis

Claims (4)

An illumination light source of an ophthalmic apparatus that irradiates an illumination light onto an eye to be examined,
a light emitting unit that emits the illumination light;
A cover for covering the light emitting unit;
one or more light transmitting portions provided in the cover at positions eccentric to a central axis of the illumination light source;
Equipped with
the cover emits the illumination light only from the light-transmitting portion,
The light transmitting portion is formed in the shape of a pair of slits that are perpendicular to and symmetrical with respect to the central axis . The illumination light source according to claim 1, wherein at least a portion of the area of the outer or inner surface of the cover that is different from the light-transmitting portion is a reflective surface. An ophthalmic apparatus comprising the illumination light source according to claim 1 or 2 . 4. The ophthalmic apparatus according to claim 3 , further comprising a diaphragm having a ring-shaped opening through which the illumination light emitted from the illumination light source passes.

Images