US-20260123834-A1 - OPHTHALMIC APPARATUS

US20260123834A1US 20260123834 A1US20260123834 A1US 20260123834A1US-20260123834-A1

Abstract

An ophthalmic apparatus includes an objective lens, an illumination optical system, an optical scanner, an imaging optical system, and a pupil division member. The illumination optical system includes an illumination diaphragm with one or more illumination openings, and is configured to irradiate slit-shaped illumination light. The optical scanner is configured to deflect the illumination light to guide the deflected illumination light to the eye to be examined. The imaging optical system is configured to guide returning light of the illumination light from the eye to be examined to an image sensor. The pupil division member includes a photographic diaphragm with one or more photographing openings, and is configured to spatially separate optical paths of the illumination optical system and the imaging optical system. The illumination openings and the photographing openings are formed so that a pupil separation amount becomes greater than a predetermined center ghost occurrence suppression threshold.

Inventors

Sora TOMITA
Masashi Nakajima
Masaya Suzuki

Assignees

TOPCON CORPORATION

Dates

Publication Date: 20260507
Application Date: 20251031
Priority Date: 20241106

Claims (11)

1 . An ophthalmic apparatus, comprising: an objective lens; an illumination optical system including an illumination diaphragm with one or more illumination openings, the illumination diaphragm being arranged at a position substantially conjugate optically to a pupil of an eye to be examined, and configured to irradiate slit-shaped illumination light; an optical scanner arranged at a position substantially conjugate optically to the pupil, and configured to deflect the illumination light to guide the deflected illumination light to the eye to be examined via the objective lens; an imaging optical system configured to guide returning light of the illumination light from the eye to be examined to an image sensor, the returning light passing through the objective lens, the image sensor being arranged at a position substantially conjugate optically to a photographed site of the eye to be examined; and a pupil division member including a photographic diaphragm with one or more photographing openings, the photographic diaphragm being arranged at a position substantially conjugate optically to the pupil, and configured to spatially separate an optical path of the illumination optical system and an optical path of the imaging optical system, wherein the one or more illumination openings and the one or more photographing openings are formed so that a pupil separation amount becomes greater than a predetermined center ghost occurrence suppression threshold, the pupil separation amount being a shortest distance in an arrangement direction of images of the one or more illumination openings and images of the one or more photographing openings on a pupil conjugate plane at a position substantially conjugate optically to the pupil.
2 . The ophthalmic apparatus of claim 1 , wherein the one or more illumination openings and the one or more photographing openings are formed so that the pupil separation amount is approximately constant in a direction perpendicular to the arrangement direction.
3 . The ophthalmic apparatus of claim 2 , wherein the predetermined center ghost occurrence suppression threshold is determined in accordance with a working distance of the ophthalmic apparatus, a dioptric power of an eye to be examined that can be imaged, a viewing angle of the illumination light with respect to the photographed site, and a viewing angle of the returning light with respect to the fundus.
4 . The ophthalmic apparatus of claim 3 , wherein the dioptric power is a dioptric power of a high myopia eye.
5 . The ophthalmic apparatus of claim 3 , wherein when the working distance is denoted as WD, the dioptric power is denoted as D, the viewing angle of the illumination light is denoted as α, the viewing angle of the returning light is denoted as γ, and the pupil separation amount is denoted as GP, the following formula: GP > 1000 × WD 1000 + D × WD × { tan ⁡ ( α 2 ) + tan ⁡ ( γ 2 ) } ( 1 ) is satisfied.
6 . The ophthalmic apparatus of claim 1 , wherein the one or more illumination openings and the one or more photographing openings are formed so that the pupil separation amount becomes smaller than a predetermined small pupil photographable threshold.
7 . The ophthalmic apparatus of claim 6 , wherein the predetermined small pupil photographable threshold is determined in accordance with a predetermined pupil diameter for small pupil photography, a width in the arrangement direction of the images of the one or more illumination openings, and a width in the arrangement of the images of the one or more photographing openings.
8 . The ophthalmic apparatus of claim 7 , wherein when the predetermined pupil diameter for small pupil photography is dented as φ, the width in the arrangement direction of the images of the one or more illumination openings is denoted as g, the width in the arrangement direction of the images of the one or more photographing openings is dented as h, and the pupil separation amount is denoted as GP, the following formula: ϕ - ( g + h ) > GP ( 2 ) is satisfied.
9 . The ophthalmic apparatus of claim 1 , wherein the image sensor is configured to capture a light receiving result in a virtual opening region on a light receiving surface using a rolling shutter method, the virtual opening region corresponding to an irradiated region of the illumination light on the photographed site, the irradiated region being moved in a predetermined scan direction by the optical scanner.
10 . The ophthalmic apparatus of claim 9 , wherein the image sensor is a complementary metal-oxide-semiconductor image sensor.
11 . The ophthalmic apparatus of claim 1 , wherein the photographed site is a fundus.

Description

CROSS-REFERENCE TO RELATED APPLICATION This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2024-194500, filed Nov. 6, 2024; the entire contents of which are incorporated herein by reference. FIELD The disclosure relates to an ophthalmic apparatus. BACKGROUND In recent years, screening tests have been performed using ophthalmic apparatuses. Such ophthalmic apparatuses are expected to be applied to self-examinations, and further downsizing and weight saving of the ophthalmic apparatuses are desired. U.S. Pat. Nos. 7,831,106, and 8,237,835 disclose ophthalmic apparatuses configured to pattern-illuminate a fundus of an eye to be examined using slit-shaped light and to detect returning light thereof using an image sensor. These ophthalmic apparatuses can acquire clear images of the fundus of the eye to be examined with a simple configuration, by adjusting the illumination pattern and the timing of light receiving using the image sensor. In such ophthalmic apparatuses, illumination light must be incident into the eye through a pupil of the eye to be examined, and reflected light (returning light, fundus reflected light) of the illumination light from the fundus must be emitted through the pupil. Therefore, in the ophthalmic apparatuses, an image of an illumination opening, through which the illumination light passes, and an image of a photographing opening (light receiving opening), through which the reflected light passes, are separated on a pupil conjugate plane at a position substantially conjugate optically to the pupil of the eye to be examined. WO 2021/205965 discloses an ophthalmic apparatus configured to illuminate the fundus with slit-shaped illumination light passing through two illumination openings and to receive returning light, which passes through a single photographing opening, from the fundus. In this ophthalmic apparatus, the slit-shaped illumination light is generated by irradiating the illumination light onto a slit formed so as to suppress occurrence of flare. Japanese Unexamined Patent Application Publication No. 2020-06172 discloses an ophthalmic apparatus configured to fit an image of an illumination opening and an image of a photographing opening within the pupil of the eye to be photographed, by shifting an alignment reference position relative to an eye to be examined in accordance with a size of a pupil diameter. SUMMARY One aspect of some embodiments is an ophthalmic apparatus, including: an objective lens; an illumination optical system including an illumination diaphragm with one or more illumination openings, the illumination diaphragm being arranged at a position substantially conjugate optically to a pupil of an eye to be examined, and configured to irradiate slit-shaped illumination light; an optical scanner arranged at a position substantially conjugate optically to the pupil, and configured to deflect the illumination light to guide the deflected illumination light to the eye to be examined via the objective lens; an imaging optical system configured to guide returning light of the illumination light from the eye to be examined to an image sensor, the returning light passing through the objective lens, the image sensor being arranged at a position substantially conjugate optically to a photographed site of the eye to be examined; and a pupil division member including a photographic diaphragm with one or more photographing openings, the photographic diaphragm being arranged at a position substantially conjugate optically to the pupil, and configured to spatially separate an optical path of the illumination optical system and an optical path of the imaging optical system. The one or more illumination openings and the one or more photographing openings are formed so that a pupil separation amount becomes greater than a predetermined center ghost occurrence suppression threshold, the pupil separation amount being a shortest distance in an arrangement direction of images of the one or more illumination openings and images of the one or more photographing openings on a pupil conjugate plane at a position substantially conjugate optically to the pupil. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram illustrating an example of a configuration of an optical system of an ophthalmic apparatus according to embodiments. FIG. 2 is a schematic diagram illustrating an example of a configuration of an optical system of the ophthalmic apparatus according to the embodiments. FIG. 3 is a schematic diagram illustrating an example of a configuration of the optical system of the ophthalmic apparatus according to the embodiments. FIG. 4 is a schematic diagram for explaining the configuration of the optical system of the ophthalmic apparatus according to the embodiments. FIG. 5 is an explanatory diagram of an operation of the ophthalmic apparatus according to the embodiments. FIG. 6 is an explanatory diagram of an operation of the opht