WO2024195637A1 - Ophthalmic device - Google Patents

Abstract

This ophthalmic device comprises two or more light sources, an illumination optical system, a light-receiving optical system, and an optical path dividing member. The illumination optical system includes an iris diaphragm and an illumination diaphragm, and illuminates a subject eye with light from the two or more light sources via the iris diaphragm and the illumination diaphragm. The iris diaphragm is disposed at an iris conjugate position which is optically substantially conjugate with the iris of the subject eye, and has two or more openings formed therein. The illumination diaphragm is disposed at a fundus conjugate position which is optically substantially conjugate with the fundus of the subject eye. The light-receiving optical system guides return light from the subject eye to an imaging element. The optical path dividing member spatially divides the optical path of the illumination optical system and the optical path of the light-receiving optical system such that, in a plane at the iris conjugate position, images of the two or more openings are disposed in the periphery of a light reception opening through which the return light passes. The centers of the two or more openings are respectively disposed on the optical axis of a corresponding one of the two or more light sources.

Description

Ophthalmic Equipment

This invention relates to an ophthalmic device.

In recent years, screening tests have been performed using ophthalmic devices. It is expected that such ophthalmic devices will also be used for self-examination, so there is a demand for them to be even smaller and lighter.

For example, Patent Documents 1 and 2 disclose an ophthalmic device that is configured to illuminate the subject's eye with slit-shaped light and detect the return light with a CMOS (Complementary Metal Oxide Semiconductor) image sensor. This ophthalmic device is capable of acquiring an image of the subject's eye with a simple configuration by adjusting the illumination pattern and the timing of movement of the light receiving area in the CMOS image sensor.

U.S. Pat. No. 7,831,106 U.S. Pat. No. 8,237,835

It is desirable that such an ophthalmic device be configured so that an illumination opening through which slit-shaped light passes as illumination light and a light-receiving opening (photography opening) through which return light from the test eye passes as photography light are separated at the iris (pupil) of the test eye.

Furthermore, in order to suppress optical aberrations of the ocular optical system, it is desirable that the light receiving aperture is arranged on the optical axis of the ocular optical system, and that two or more illumination apertures are arranged around the light receiving aperture. In this case, the illumination light is formed by irradiating light from the light source onto an iris diaphragm arranged at a position that is approximately optically conjugate with the iris of the subject's eye. In order to uniformly illuminate an observation site such as the fundus with such illumination light, it is required that the change in the light quantity distribution (light distribution) per angle of the illumination light emitted from the iris diaphragm is small. In addition, it is necessary to generate slit-shaped light using a slit, which significantly reduces the amount of light reaching the observation site. Therefore, in order to increase the illumination efficiency, it is desirable to fully illuminate the iris diaphragm in which two or more openings are formed with light from the light source.

If the above illumination is to be achieved with a single light source, the efficiency of the amount of illumination light relative to the amount of light emitted by the light source will be extremely poor. There is also the problem that the amount of light emitted by the light source is limited in terms of heat generation. As a result, there is a problem that sufficient illumination light cannot be obtained. Furthermore, if an attempt is made to suppress the amount of heat generated in order to obtain an amount of emitted light, a cooling mechanism such as air cooling will need to be installed, and the configuration for preventing dust inside the device using air cooling will become complicated.

The present invention was made in consideration of these circumstances, and one of its objectives is to provide a new technology for brightly illuminating the observation area with a simple configuration.

One aspect of the embodiment is an ophthalmic device including two or more light sources, an illumination optical system, a light receiving optical system, and an optical path splitting member. The illumination optical system includes an iris diaphragm and an illumination diaphragm, and illuminates the subject's eye with light from the two or more light sources via the iris diaphragm and the illumination diaphragm. The iris diaphragm is disposed at an iris conjugate position that is optically approximately conjugate with the iris of the subject's eye, and two or more apertures are formed therein. The illumination diaphragm is disposed at a fundus conjugate position that is optically approximately conjugate with the fundus of the subject's eye. The light receiving optical system guides return light from the subject's eye to an imaging element. The optical path splitting member spatially splits the optical path of the illumination optical system and the optical path of the light receiving optical system so that images of the two or more apertures are disposed around the light receiving aperture through which the return light passes on a plane at the iris conjugate position. The centers of the two or more corresponding apertures are disposed on the optical axes of the two or more light sources.

This invention provides a new technology for brightly illuminating an observation area using a simple configuration.

1 is a schematic diagram illustrating an example of the configuration of an optical system of an ophthalmic apparatus according to a first embodiment. 1 is a schematic diagram illustrating an example of the configuration of an optical system of an ophthalmic apparatus according to a first embodiment. 1 is a schematic diagram illustrating an example of the configuration of an optical system of an ophthalmic apparatus according to a first embodiment. 1 is a schematic diagram for explaining an optical system of an ophthalmic apparatus according to a first embodiment. FIG. 1 is a schematic diagram for explaining an optical system of an ophthalmic apparatus according to a first embodiment. FIG. 1 is a schematic diagram for explaining an optical system of an ophthalmic apparatus according to a first embodiment. FIG. 3A and 3B are schematic diagrams for explaining the operation of the ophthalmologic apparatus according to the first embodiment. 3A and 3B are schematic diagrams for explaining the operation of the ophthalmologic apparatus according to the first embodiment. 3A and 3B are schematic diagrams for explaining the operation of the ophthalmologic apparatus according to the first embodiment. 2 is a schematic diagram showing an example of the configuration of a control system of the ophthalmic apparatus according to the first embodiment. FIG. FIG. 4 is a flowchart of an operation example of the ophthalmologic apparatus according to the first embodiment. 13 is a schematic diagram showing an example of the configuration of an optical system of an ophthalmic apparatus according to a second embodiment. FIG. 13 is a schematic diagram showing an example of the configuration of an optical system of an ophthalmic apparatus according to a second embodiment. FIG. 13 is a schematic diagram showing an example of the configuration of an optical system of an ophthalmic apparatus according to a third embodiment. FIG. 13 is a schematic diagram showing an example of the configuration of an optical system of an ophthalmic apparatus according to a third embodiment. FIG.

An example of an embodiment of an ophthalmic device according to the present invention will be described in detail with reference to the drawings. Note that the contents of the documents described in this specification may be appropriately used as the contents of the following embodiment.

The ophthalmic device according to the embodiment is capable of acquiring an image of the subject's eye by a slit scanning method using slit-shaped illumination light. Specifically, the ophthalmic device uses an optical scanner to illuminate a specific part of the subject's eye while moving a slit-shaped irradiation position (irradiation range) where the illumination light is irradiated, and receives return light from the subject's eye using an image sensor in which light receiving elements are arranged one-dimensionally or two-dimensionally. The result of receiving the return light is read out from the light receiving elements at the return light receiving position corresponding to the illumination light irradiation position, in synchronization with the timing of the movement of the illumination light irradiation position.

In an ophthalmic device, an illumination opening through which slit-shaped illumination light passes and a light-receiving opening (imaging opening) through which return light from the test eye as imaging light passes are separated at the iris (pupil) of the test eye (or at a position that is approximately optically conjugate with the iris (pupil) (iris (pupil) conjugate position)). In order to suppress optical aberrations in the light-receiving system, the light-receiving opening is arranged on the optical axis, and two or more illumination openings are arranged around the light-receiving opening.

The ophthalmic device includes two or more light sources, an illumination optical system, a light receiving optical system, and an optical path splitting member. The illumination optical system includes an iris diaphragm arranged at a position that is approximately optically conjugate with the iris of the subject's eye, and a slit as an illumination diaphragm arranged at a position that is approximately optically conjugate with an observation site of the subject's eye (e.g., the fundus). Two or more openings are formed in the iris diaphragm. Each of the two or more light sources is provided corresponding to each of the two or more openings formed in the iris diaphragm. In this case, the center of a corresponding one of the two or more openings formed in the iris diaphragm is located on the optical axis of each of the two or more light sources.

In some embodiments, each of the two or more light sources is positioned adjacent to a corresponding one of the two or more openings formed in the iris diaphragm such that the optical axis of the light source passes through the center of the light-emitting area of the light source. In some embodiments, each of the two or more light sources is positioned at a position that is approximately optically conjugate with the corresponding one of the two or more openings formed in the iris diaphragm. In some embodiments, the emitted light of each of the two or more light sources is configured to be guided through a light-guiding member to the corresponding one of the two or more openings formed in the iris diaphragm.

The illumination optical system forms a slit-shaped illumination light by illuminating an iris diaphragm with light from two or more light sources and illuminating a slit with the illumination light that has passed through two or more openings formed in the iris diaphragm corresponding to each of the two or more light sources. The light receiving optical system receives the return light from the observation area illuminated by the illumination light through the light receiving opening with an image sensor.

In a plane at the iris conjugate position, which is a position that is approximately optically conjugate with the iris of the subject's eye, images of two or more apertures formed in the iris diaphragm are formed. The optical path splitting member spatially splits the optical path of the illumination optical system and the optical path of the light receiving optical system so that the images of two or more apertures formed in the iris diaphragm are arranged around the light receiving aperture in the plane at the iris conjugate position (plane that intersects with the optical axis).

This improves the efficiency of use of the light emitted by the light source, thereby suppressing an increase in the amount of light emitted by the light source. This reduces the amount of heat generated by each of two or more light sources, making it possible to brightly illuminate the observation area with a simple configuration. In particular, by using a high-brightness light source that becomes brighter the smaller the light-emitting area, the efficiency of use of the light emitted by the light source can be further improved.

For example, it is conceivable to convert the magnification of light from a single light source using a lens or the like, and then enlarge and project the light onto the iris diaphragm. In this case, due to the optical relationship between lateral magnification and angular magnification, the directionality of the illumination light that passes through the opening formed in the iris diaphragm increases, making it difficult to sufficiently illuminate the longitudinal direction of the opening formed in the slit. In contrast, the above configuration makes it possible to uniformly illuminate the entire iris diaphragm. As a result, it is possible to increase the size of the illumination opening (image of the opening formed in the iris diaphragm), increasing the numerical aperture (Numerical Aperture: NA) at the observation site, and enabling clearer observation of the observation site.

In some embodiments, the observation site is the anterior segment or the posterior segment. The anterior segment includes the cornea, iris, lens, ciliary body, and Zinn's zonule. The posterior segment includes the vitreous body, fundus, or areas adjacent thereto (retina, choroid, sclera, etc.).

The control method of the ophthalmic device according to the embodiment includes one or more steps for implementing processing executed by a processor (computer) in the ophthalmic device according to the embodiment. The program according to the embodiment causes the processor to execute each step of the control method of the ophthalmic device according to the embodiment. The recording medium according to the embodiment is a non-transitory recording medium (storage medium) on which the program according to the embodiment is recorded.

In this specification, the term "processor" refers to a circuit such as a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), an ASIC (Application Specific Integrated Circuit), or a programmable logic device (e.g., an SPLD (Simple Programmable Logic Device), a CPLD (Complex Programmable Logic Device), or an FPGA (Field Programmable Gate Array)). The processor realizes the functions of the embodiment by, for example, reading and executing a program stored in a memory circuit or a storage device.

In the following embodiments, two openings are formed in the iris diaphragm, and the observation site is the fundus. In addition, a position optically conjugate with the iris (pupil) of the subject's eye or its vicinity is referred to as the "iris (pupil) conjugate position," and a position optically conjugate with the fundus of the subject's eye or its vicinity is referred to as the "fundus conjugate position." In the following embodiments, unless otherwise specified, the iris conjugate position may be replaced with the pupil conjugate position.

Hereinafter, the X direction is the direction perpendicular to the optical axis direction of the objective lens (left-right direction), the Y direction is the direction perpendicular to the optical axis direction of the objective lens (up-down direction), and the Z direction is the optical axis direction of the objective lens.

First Embodiment
[Optical system configuration]
1 to 3 show an example of the configuration of the optical system of the ophthalmic apparatus according to the first embodiment. Fig. 1 shows an example of the configuration of the optical system of the ophthalmic apparatus 1 according to the first embodiment. Fig. 2 is a schematic diagram of an example of the configuration of the iris diaphragm 21 of Fig. 1. Fig. 3 is a schematic diagram of the configuration of the optical system of the illumination optical system 20 of Fig. 1 in the YZ plane. In Figs. 1 to 3, similar parts are given the same reference numerals, and descriptions thereof will be omitted as appropriate.

As shown in FIG. 1, the ophthalmic device 1 includes an illumination optical system 20 including light sources 10A and 10B, an optical scanner 30, a projection optical system 35, a photographing optical system 40, and an image capture device 50. In some embodiments, the light sources 10A and 10B are provided outside the illumination optical system 20. In some embodiments, the illumination optical system 20 includes at least one of the optical scanner 30 and the projection optical system 35. In some embodiments, the photographing optical system 40 includes an image capture device 50. In some embodiments, the projection optical system 35 or the illumination optical system 20 includes the optical scanner 30.

(Illumination optical system 20)
The illumination optical system 20 generates slit-shaped illumination light using the light from the light sources 10A and 10B, and guides the generated illumination light to the optical scanner 30.

Such an illumination optical system 20 includes light sources 10A and 10B, an iris diaphragm 21, a condenser lens 23, a slit 22 as an illumination diaphragm, and a relay lens system RL1. The iris diaphragm 21 has two openings formed at positions that are offset from a position corresponding to the optical axis O of the illumination optical system 20. The light source 10A is provided corresponding to one of the two openings. The light source 10B is provided corresponding to the other of the two openings.

(Light sources 10A, 10B)
The light sources 10A and 10B include visible light sources that generate light in the visible region. For example, the light sources 10A and 10B generate light having a central wavelength in the wavelength range of 420 nm to 700 nm. Such light sources 10A and 10B are The light source 10A includes, for example, an LED (Light Emitting Diode) and emits light with a light amount distribution w0 as shown in Fig. 3. The configuration of the light source 10A may be similar to the configuration of the light source 10B.

(Iris Diaphragm 21)
The iris diaphragm 21 (specifically, an opening described later) is configured to be disposed at an iris conjugate position Q of the subject's eye E by alignment between the subject's eye E and the optical system. The iris diaphragm 21 has two openings formed at positions away from the optical axis O.

2, the iris diaphragm 21 is formed with a first opening 21A and a second opening 21B. Specifically, a position corresponding to the optical axis O of the illumination optical system 20 is disposed on a straight line connecting the centers of the first opening 21A and the second opening 21B (corresponding to centers Lca and Lcb shown in FIG. 5 described later). For example, the first opening 21A and the second opening 21B are formed symmetrically with respect to a straight line that passes through the position of the optical axis O and extends in a direction corresponding to the longitudinal direction of the slit 22. Each of the first opening 21A and the second opening 21B has a circular segment shape (crescent shape). The arch is an area surrounded by a minor arc of a circle or an ellipse and a chord of this minor arc. For example, the direction of the chord of the arch shape is approximately parallel to the direction corresponding to the longitudinal direction of the opening formed in the slit 22.

The opening formed in the iris diaphragm 21 determines the incident position (incident shape) of the illumination light on the iris of the subject's eye E. For example, by forming a first opening 21A and a second opening 21B as shown in FIG. 2, when the pupil center of the subject's eye E is positioned on the optical axis O, the illumination light can be made to enter the eye from a position eccentric to the pupil center (specifically, a position point-symmetrical with respect to the pupil center).

In the first embodiment, the light source 10A is disposed adjacent to the first opening 21A. The light source 10B is disposed adjacent to the second opening 21B.

Figure 4 shows a schematic of the light-emitting area of light source 10A. Figure 4 shows a schematic of the light-emitting area of a surface-mounted LED serving as light source 10A from the emission direction. Note that while Figure 4 shows the light-emitting area of light source 10A, the light-emitting area of light source 10B is similar.

The light source 10A includes a light-emitting element (LED element) and a substrate (not shown) on which the light-emitting element is mounted, and the light-emitting element and the substrate are electrically connected via a bonding wire for supplying an electrical signal to the light-emitting element.

The light source 10A emits light from a light-emitting region Ld of a substantially rectangular shape on the light-emitting element. At this time, the light emission intensity increases the closer one gets to the center Lc from the periphery of the light-emitting region Ld. In FIG. 4, the light emission intensity range in the light-emitting region LD is divided into multiple ranges, and the light emission intensity of each region is illustrated diagrammatically by dividing the light-emitting region LD with dashed lines. Note that a bonding region for electrically connecting the above-mentioned bonding wire is provided on the periphery of the light-emitting region Ld, which impairs the symmetry of the light emission intensity distribution of the light-emitting region Ld, but the light-emitting region Ld is substantially substantially rectangular.

The centers of the corresponding first and second openings 21A and 21B formed in the iris diaphragm 21 are located on the optical axes of the light sources 10A and 10B. The center of the opening may be the center of both the long and short sides of the opening, or the center of gravity of the opening. The long side of the opening means the long side of a rectangle circumscribing the opening, and the short side of the opening means the short side of a rectangle circumscribing the opening.

Specifically, the light source 10A is disposed adjacent to the iris diaphragm 21 so that the center of the first opening 21A is located on its optical axis. Here, the optical axis of the light source 10A is an optical axis passing through the center Lc of the light-emitting area Ld of the light source 10A. The center Lc of the light-emitting area Ld may be, for example, the center of both the longitudinal direction and the lateral direction of the light-emitting area Ld (a rectangle circumscribing the light-emitting area Ld), or the center of gravity of the light-emitting area Ld. For example, the light source 10A is disposed so as to be in contact with the iris diaphragm 21, or is fixed to the iris diaphragm 21 via a predetermined fixing member. Furthermore, the light source 10B is disposed adjacent to the iris diaphragm 21 so that the center of the second opening 21B is located on its optical axis. Here, the optical axis of the light source 10B is an optical axis passing through the center of the light-emitting area of the light source 10B. The center of this light-emitting area may be, for example, the center of both the longitudinal direction and the lateral direction of the light-emitting area, or the center of gravity of the light-emitting area. For example, the light source 10B may be disposed so as to be in contact with the iris diaphragm 21, or may be fixed to the iris diaphragm 21 via a predetermined fixing member.

In some embodiments, each of the light sources 10A and 10B is positioned so that the diagonal direction of the approximately rectangular light-emitting region approximately coincides with the longitudinal direction of the corresponding opening.

FIG. 5 shows a schematic example of the arrangement of light sources 10A and 10B relative to the iris diaphragm 21 according to the first embodiment. FIG. 5 shows an example of the arrangement of light sources 10A and 10B when the iris diaphragm 21 is viewed from the condenser lens 23 side. In FIG. 5, parts that are the same as those in FIG. 2 or FIG. 4 are given the same reference numerals, and descriptions thereof will be omitted as appropriate.

The light source 10A is arranged so that the diagonal direction of the light-emitting region Ld approximately coincides with the longitudinal direction of the first opening 21A formed in the iris diaphragm 21. The diagonal direction corresponds to the direction in which the diagonal extends. The diagonal of the light-emitting region may be the diagonal of a quadrangular region that is inscribed or circumscribed in the light-emitting region (e.g., a light-emitting region with a predetermined light emission intensity or higher). The longitudinal direction of the first opening 21A may be the longitudinal direction (e.g., the X direction) of a rectangle that is circumscribed in the first opening 21A.

For example, light source 10A is arranged so that the center 21Aa of first opening 21A formed in iris diaphragm 21 is located on the optical axis passing through the center Lca of light-emitting region Ld, and the diagonal direction of the light-emitting region approximately coincides with the longitudinal direction of first opening 21A formed in iris diaphragm 21. As shown in FIG. 5, when iris diaphragm 21 is viewed from the optical axis O, light source 10A is arranged so that the center 21Aa of first opening 21A coincides with the center Lca of the light-emitting region.

Similarly, the light source 10B is arranged so that the diagonal direction of the light-emitting region approximately coincides with the longitudinal direction of the second opening 21B formed in the iris diaphragm 21. The longitudinal direction of the second opening 21B may be the longitudinal direction of a rectangle circumscribing the second opening 21B (e.g., the X direction).

For example, light source 10B is arranged so that center 21Ba of second opening 21B formed in iris diaphragm 21 is located on the optical axis passing through center Lcb of the light-emitting region, and the diagonal direction of the light-emitting region approximately coincides with the longitudinal direction of second opening 21B formed in iris diaphragm 21. As shown in FIG. 5, when iris diaphragm 21 is viewed from optical axis O, light source 10B is arranged so that center 21Ba of second opening 21B coincides with center Lcb of the light-emitting region.

With the configuration shown in FIG. 5, when the iris diaphragm 21 is viewed from the condenser lens 23 side, the exposed area of the light emitting region of the light source 10A can be maximized through the first opening 21A, and the exposed area of the light emitting region of the light source 10B can be maximized through the second opening 21B. This allows a greater amount of light to pass through the iris diaphragm 21. In particular, when the longitudinal length of the opening formed in the iris diaphragm 21 is longer than the length of one side of the rectangular light emitting region of the light source, it is possible to improve the efficiency of use of the amount of light emitted by the light source by arranging the light source so that the longitudinal direction and diagonal direction of the opening are approximately aligned as shown in FIG. 5.

In FIG. 2, the iris diaphragm 21 is formed with a first opening 21A and a second opening 21B, but the embodiment is not limited to the number of openings formed in the iris diaphragm 21. For example, the iris diaphragm 21 may be formed with three or more openings. For example, the iris diaphragm 21 is formed with three or more openings at approximately equal angular intervals in an arc shape centered on the optical axis O. This makes it possible to allow illumination light to be incident on the eye approximately evenly from three or more incident positions.

(Condenser lens 23)
The condenser lens 23 is a lens having refractive power in both the X direction and the Y direction. The condenser lens 23 refracts the light from the light source 10A that has passed through the first opening 21A and guides it to the opening formed in the slit 22, and refracts the light from the light source 10B that has passed through the second opening 21B and guides it to the opening formed in the slit 22.

When the focal length of the condenser lens 23 is fc, as shown in FIG. 3, the iris diaphragm 21 is disposed at the front focal position of the condenser lens 23 (i.e., at a position separated from the condenser lens 23 by the focal length fc). Also, the slit 22 is disposed at the rear focal position of the condenser lens 23.

If the shape of the opening formed in the iris diaphragm 21 is arched or rectangular as shown in FIG. 5, the condenser lens 23 may be a toric lens, or a first cylinder lens having refractive power only in the Y direction (YZ plane) and a second cylinder lens having refractive power only in the X direction (XZ plane).

(Slit 22)
1, the slit 22 (specifically, an opening described later) is configured to be arranged at a fundus conjugate position of the eye E as an illumination aperture, an illumination slit, or a fundus slit by alignment between the eye E and the optical system. For example, the slit 22 has an opening (slit-shaped opening) formed in a direction corresponding to a line direction (row direction) read from an image sensor 51 described later by a rolling shutter method. In this embodiment, the slit 22 has a rectangular opening formed such that the longitudinal direction is the X direction and the lateral direction is the Y direction. The opening formed in the slit 22 defines an irradiation pattern of illumination light on the fundus Ef of the eye E.

The slit 22 can be moved in the optical axis direction of the illumination optical system 20 by a moving mechanism (moving mechanism 22D described below). The moving mechanism moves the slit 22 in the optical axis direction under the control of the control unit 100 described below. For example, the control unit 100 controls the moving mechanism depending on the condition of the subject's eye E. This makes it possible to move the position of the slit 22 depending on the condition of the subject's eye E (specifically, the refractive power and the shape of the fundus Ef).

In some embodiments, the light sources 10A and 10B, iris diaphragm 21, condenser lens 23, and slit 22 shown in FIG. 1 are housed in an optical unit. This optical unit is configured to be moved in the optical axis direction of the illumination optical system 20. As a result, the above optical elements are moved integrally in the optical axis direction of the illumination optical system 20. In this case, a moving mechanism (moving mechanism 22D described below) is controlled by a control unit 100 described below and moves the above optical unit in the optical axis direction. For example, the control unit 100 controls the moving mechanism depending on the state of the subject's eye E. As a result, the position of the slit 22 included in the optical unit can be moved depending on the state of the subject's eye E (specifically, the refractive power and the shape of the fundus Ef).

In some embodiments, the slit 22 is configured so that at least one of the position and shape of the opening is changed depending on the state of the subject's eye E without being moved in the optical axis direction. The function of such a slit 22 is realized by, for example, a liquid crystal shutter.

(Relay lens system RL1)
1, a relay lens system RL1 is disposed between the optical scanner 30 and the slit 22. The relay lens system RL1 includes one or more lenses. The rear focal position of the relay lens system RL1 is disposed at an iris conjugate position of the subject's eye E.

As described below, the optical scanner 30, which is placed at the iris conjugate position of the test eye E, is placed at or near the rear focal position of the relay lens system RL1. Therefore, even if the slit 22 is moved in the optical axis direction according to the state (refractive power) of the test eye E, the size of the slit image (image formed by light that has passed through the opening formed in the slit 22) projected onto the fundus Ef does not change, regardless of the state of the test eye E. This means that the projection magnification of the slit image onto the fundus Ef does not change even if the slit 22 is moved in the optical axis direction.

In other words, by placing the optical scanner 30 at (or near) the rear focal position of the relay lens system RL1, the relay lens system RL1, the relay lenses 41 and 44, and the objective lens 46 form a Bardal optical system (see Figure 1).

Therefore, the projection angle (projection magnification) (longitudinal and lateral directions of the slit 22) of the slit image relative to the visual axis of the subject's eye E can be kept constant regardless of the condition of the subject's eye E (such as refractive power). As a result, the size of the slit image does not change regardless of the condition of the subject's eye E, making it possible to keep the deflection operation speed of the optical scanner 30 constant, and simplifying the control of the optical scanner 30.

In addition, regardless of the condition of the subject's eye E (such as refractive power), the projection angle of the slit image (projection magnification) relative to the visual axis of the subject's eye E is constant, so the illuminance of the slit image at the fundus Ef can be made constant.

Furthermore, when an image is acquired with a predetermined shooting angle in an ophthalmic device, since the projection magnification is constant as described above, there is no need to provide a margin in the longitudinal length of the slit 22 provided to acquire a slit image of a predetermined size.

As described above, in the illumination optical system 20, the light from the light source 10A having the light quantity distribution w0 in the region with the maximum emission intensity passes through the first opening 21A formed in the iris diaphragm 21. Also, the light from the light source 10B having the light quantity distribution w0 in the region with the maximum emission intensity passes through the second opening 21B formed in the iris diaphragm 21. The condenser lens 23 refracts the light that has passed through the first opening 21A and the second opening 21B and guides it to the opening formed in the slit 22. The light guided to the slit 22 passes through the opening formed in the slit 22 and is output as slit-shaped illumination light. The slit-shaped illumination light passes through the relay lens system RL1 and is guided to the optical scanner 30.

(Optical scanner 30)
The optical scanner 30 is configured to be disposed at an iris conjugate position of the subject's eye E by aligning the subject's eye E with the optical system. The optical scanner 30 deflects slit-shaped illumination light (slit-shaped light passing through an opening formed in the slit 22) transmitted through the relay lens system RL1. Specifically, the optical scanner 30 deflects the slit-shaped illumination light for sequentially illuminating a predetermined illumination range of the fundus Ef while changing the deflection angle within a predetermined deflection angle range with the iris of the subject's eye E or its vicinity as the scanning center position, and guides the slit-shaped illumination light to the projection optical system 35. The optical scanner 30 is capable of deflecting the illumination light one-dimensionally or two-dimensionally.

When deflecting one-dimensionally, the optical scanner 30 includes a galvanometer scanner that deflects the illumination light within a predetermined deflection angle range based on a predetermined deflection direction. When deflecting two-dimensionally, the optical scanner 30 includes a first galvanometer scanner and a second galvanometer scanner. The first galvanometer scanner deflects the illumination light so as to move the irradiation position of the illumination light in a horizontal direction perpendicular to the optical axis of the illumination optical system 20. The second galvanometer scanner deflects the illumination light deflected by the first galvanometer scanner so as to move the irradiation position of the illumination light in a vertical direction perpendicular to the optical axis of the illumination optical system 20. Examples of scanning modes for moving the irradiation position of the illumination light by the optical scanner 30 include horizontal scanning, vertical scanning, cross scanning, radial scanning, circular scanning, concentric circular scanning, and spiral scanning.

(Projection Optical System 35)
The projection optical system 35 guides the illumination light deflected by the optical scanner 30 to the fundus Ef of the subject's eye E. In the embodiment, the projection optical system 35 guides the illumination light deflected by the optical scanner 30 to the fundus Ef via a hole mirror 45 serving as an optical path splitting member described later.

The projection optical system 35 includes a relay lens 41, a black dot plate 42, a reflecting mirror 43, and a relay lens 44. Each of the relay lenses 41 and 44 includes one or more lenses.

(Black dot plate 42)
The black dot plate 42 is disposed at a position that is approximately optically conjugate with the lens surface of the objective lens 46 or in its vicinity.

In this type of projection optical system 35, the illumination light deflected by the optical scanner 30 passes through the relay lens 41, passes through the black dot plate 42, is reflected by the reflecting mirror 43 toward the relay lens 44, passes through the relay lens 44, and is guided to the hole mirror 45.

(Photographing Optical System 40)
The imaging optical system 40 guides the illumination light guided through the projection optical system 35 to the fundus Ef of the test eye E, and also guides the return light from the test eye E to the imaging device 50. The return light from the test eye E is scattered light (reflected light) of the illumination light incident on the test eye E. In some embodiments, the return light from the test eye E includes scattered light (reflected light) of the illumination light incident on the test eye E, and fluorescence and its scattered light whose excitation light is the illumination light incident on the test eye E.

In the imaging optical system 40, the optical path of the illumination light from the projection optical system 35 and the optical path of the return light from the test eye E (fundus Ef) are spatially separated. By using a hole mirror 45 as an optical path separating member that separates these optical paths, it is possible to perform pupil separation of the illumination light and its return light.

The imaging optical system 40 includes a hole mirror 45, an objective lens 46, a focusing lens 47, a relay lens 48, and an imaging lens 49. The relay lens 48 includes one or more lenses.

(Hole mirror 45)
The hole mirror 45 has a hole formed therein, which is located on the optical axis O1 of the photographing optical system 40. The hole mirror 45 is configured so that the hole is located at an iris conjugate position of the subject's eye E by alignment between the subject's eye E and the optical system. The hole mirror 45 reflects illumination light from the projection optical system 35 toward the objective lens 46 in the peripheral area of the hole. Such a hole mirror 45 functions as a photographing aperture.

The hole mirror 45 also functions as an optical path splitting member that spatially splits the optical path of the illumination light that has passed through the slit 22 and the optical path of the return light from the subject's eye E.

Figure 6 shows a schematic representation of an image formed on a plane that intersects with the optical axis at the iris conjugate position Q. Figure 6 shows a schematic representation of an image formed, for example, on the reflecting surface of a hole mirror 45 that is placed at the iris conjugate position Q.

A photographing aperture SA is formed as a light receiving aperture in the hole of the hole mirror 45, which is positioned so that the optical axis O1 passes through. Return light from the subject's eye E passes through the photographing aperture SA. In the peripheral area of the hole of the hole mirror 45, an image IA1 of the first aperture 21A and an image IA2 of the second aperture 21B of the iris diaphragm 21 are formed as illumination apertures.

In other words, the hole mirror 45 is configured to spatially divide the optical path of the illumination optical system 20 (projection optical system 35) and the optical path of the imaging optical system 40 arranged in the direction of the optical axis passing through the hole, and to guide the illumination light reflected in the peripheral area of the hole to the fundus Ef.

(Focusing lens 47)
The focusing lens 47 can be moved in the optical axis direction of the photographing optical system 40 by a moving mechanism (not shown). The moving mechanism moves the focusing lens 47 in the optical axis direction under the control of a control unit 100 (described later). This allows the return light from the subject's eye E, which has passed through the hole of the hole mirror 45, to be imaged on the light receiving surface of the image sensor 51 of the imaging device 50 according to the state of the subject's eye E.

In this type of imaging optical system 40, the illumination light from the projection optical system 35 is reflected toward the objective lens 46 in the peripheral area of the hole formed in the hole mirror 45. The illumination light reflected in the peripheral area of the hole mirror 45 is refracted by the objective lens 46 and enters the eye through the pupil of the subject's eye E, illuminating the fundus Ef of the subject's eye E.

The return light from the subject's eye E is refracted by the objective lens 46, passes through the hole in the hole mirror 45, transmits through the focusing lens 47, transmits through the relay lens 48, and is imaged by the imaging lens 49 on the light receiving surface of the image sensor 51 of the imaging device 50.

(Imaging device 50)
The imaging device 50 includes an image sensor 51 that receives return light guided from the fundus Ef of the subject's eye E through the imaging optical system 40. The imaging device 50 is controlled by a control unit 100 (described later) and is capable of controlling the reading of the results of receiving the return light.

(Image sensor 51)
The image sensor 51 functions as a pixelated light receiver. The light receiving surface (detection surface, imaging surface) of the image sensor 51 can be arranged at a position that is approximately optically conjugate with the fundus Ef.

The light reception results from the image sensor 51 are read out using the rolling shutter method under the control of the control unit 100, which will be described later.

Such an image sensor 51 includes a CMOS image sensor. In this case, the image sensor 51 includes a plurality of pixels arranged in a row direction, each of which is a group of pixels (light receiving elements) arranged in a column direction. Specifically, the image sensor 51 includes a plurality of pixels arranged two-dimensionally, a plurality of vertical signal lines, and a horizontal signal line. Each pixel includes a photodiode (light receiving element) and a capacitor. The plurality of vertical signal lines are provided for each pixel group in the column direction (vertical direction) perpendicular to the row direction (horizontal direction). Each vertical signal line is selectively electrically connected to a pixel group in which a charge corresponding to the light receiving result is accumulated. The horizontal signal line is selectively electrically connected to the plurality of vertical signal lines. Each pixel accumulates a charge corresponding to the light receiving result of the return light, and the accumulated charge is read out sequentially, for example, for each pixel group in the row direction. For example, a voltage corresponding to the charge accumulated in each pixel is supplied to the vertical signal line for each line in the row direction. The plurality of vertical signal lines are selectively electrically connected to the horizontal signal line. By performing the above-mentioned row-direction line-by-line readout operation in the vertical direction, it is possible to read out the light reception results of multiple pixels arranged two-dimensionally.

By capturing (reading) the results of receiving the return light from such an image sensor 51 using a rolling shutter method, a received light image corresponding to a desired virtual opening shape extending in the row direction is obtained. This type of control is disclosed, for example, in the specification of U.S. Patent No. 8,237,835.

FIG. 7 is a diagram illustrating the operation of the ophthalmologic apparatus 1 according to the embodiment. FIG. 7 shows a schematic diagram of the irradiation range IP of the slit-shaped illumination light irradiated onto the fundus Ef and the virtual aperture range OP on the light receiving surface SR of the image sensor 51.

For example, the control unit 100 described below deflects the slit-shaped illumination light formed by the illumination optical system 20 using the optical scanner 30. As a result, the irradiation range IP of the slit-shaped illumination light is sequentially moved in a direction (e.g., vertical direction) perpendicular to the slit direction (e.g., row direction, horizontal direction) on the fundus Ef.

A virtual aperture range OP is set on the light receiving surface SR of the image sensor 51 by changing the pixels to be read on a line-by-line basis using the control unit 100 described below. It is desirable that the aperture range OP is the light receiving range IP' of the return light on the light receiving surface SR or a range wider than the light receiving range IP'. The control unit 100 described below executes movement control of the aperture range OP in synchronization with the movement control of the irradiation range IP of the illumination light. This makes it possible to obtain high-quality images of the fundus Ef with strong contrast using a simple configuration without being affected by unnecessary scattered light.

FIGS. 8 and 9 show schematic examples of control timing of the rolling shutter method for the image sensor 51. FIG. 8 shows an example of the timing of read control for the image sensor 51. FIG. 9 shows the movement control timing of the illumination light irradiation range IP (light receiving range IP') superimposed on the read control timing of FIG. 8. In FIG. 8 and FIG. 9, the horizontal axis represents the number of rows in the image sensor 51, and the vertical axis represents time.

Note that, for ease of explanation, in Figs. 8 and 9, the number of rows in the image sensor 51 is described as 1920, but the configuration according to the embodiment is not limited to this number of rows. Also, for ease of explanation, in Fig. 9, the slit width (width in the row direction) of the slit-shaped illumination light is described as 40 rows.

The row-direction readout control includes reset control, exposure control, charge transfer control, and output control. Reset control is a control for initializing the amount of charge accumulated in the pixels in the row direction. Exposure control is a control for shining light on the photodiode and accumulating a charge corresponding to the amount of light received in the capacitor. Charge transfer control is a control for transferring the amount of charge accumulated in the pixel to the vertical signal line. Output control is a control for outputting the amount of charge accumulated in multiple vertical signal lines via the horizontal signal line. In other words, as shown in FIG. 8, the readout time T of the amount of charge accumulated in the pixels in the row direction is the sum of the time Tr required for reset control, the time (exposure time) Te required for exposure control, the time Tc required for charge transfer control, and the time Tout required for output control.

In FIG. 8, the read start timing (start timing of time Tc) is shifted row by row to obtain the light reception results (amount of charge) accumulated in pixels of a desired range in the image sensor 51. For example, if the pixel range shown in FIG. 8 is an image for one frame, the frame rate FR is uniquely determined.

In this embodiment, the irradiation position on the fundus Ef of illumination light having a slit width corresponding to a number of rows is sequentially shifted in a direction corresponding to the column direction on the fundus Ef.

For example, as shown in FIG. 9, the irradiation position of the illumination light on the fundus Ef is shifted row by row in a direction corresponding to the column direction for each predetermined shift time Δt. The shift time Δt is obtained by dividing the exposure time Te of the pixel in the image sensor 51 by the slit width of the illumination light (e.g., 40) (Δt=Te/40). Synchronized with the timing of moving the irradiation position, the timing to start reading out each row of pixels is delayed and started for each row by shift time Δt. This makes it possible to obtain high-quality images of the fundus Ef with strong contrast with simple control in a short time.

In some embodiments, the image sensor 51 comprises one or more line sensors.

The slit 22 is an example of an "illumination diaphragm" according to the embodiment. The photographing optical system 40 is an example of a "light receiving optical system" according to the embodiment. The hole mirror 45 is an example of an "optical path coupling member" according to the embodiment.

[Control system configuration]
FIG. 10 is a block diagram showing an example of the configuration of a control system (processing system) of the ophthalmologic apparatus 1 according to the embodiment.

The control system of the ophthalmic device 1 is configured around the control unit 100. Note that at least a part of the configuration of the control system may be included in the ophthalmic device 1.

(Control unit 100)
The control unit 100 controls each unit of the ophthalmic apparatus 1. The control unit 100 includes a main control unit 101 and a storage unit 102. The main control unit 101 includes a processor, and executes processing according to a program stored in the storage unit 102, thereby executing control processing of each unit of the ophthalmic apparatus 1.

(Main control unit 101)
The main control unit 101 controls the illumination optical system 20 , the optical scanner 30 , the photographing optical system 40 , the image capturing device 50 , and the data processing unit 200 .

The control of the illumination optical system 20 includes the control of the light source 10 and the control of the moving mechanism 22D. The control of the light source 10 includes switching the light source on and off (or the wavelength region of light) and changing the light amount of the light source. The moving mechanism 22D moves the slit 22 (or the optical unit described above) in the optical axis direction of the illumination optical system 20. The main control unit 101 controls the moving mechanism 22D according to the state of the subject eye E to place the slit 22 at a position corresponding to the state of the subject eye E. The state of the subject eye E includes the shape of the fundus Ef, the refractive power, and the axial length. The refractive power can be obtained from a known eye refractive power measuring device such as those disclosed in JP-A-61-293430 or JP-A-2010-259495. The axial length can be obtained from the measurement value of a known axial length measuring device or an optical coherence tomography.

For example, first control information in which the position of the slit 22 on the optical axis of the illumination optical system 20 is previously associated with the refractive power is stored in the storage unit 102. The main control unit 101 refers to the first control information to identify the position of the slit 22 corresponding to the refractive power, and controls the movement mechanism 22D so that the slit 22 is positioned at the identified position.

In some embodiments, as the slit 22 moves, the main control unit 101 changes the position and orientation of the light source 10 in response to changes in the light intensity distribution of the light passing through the opening formed in the slit 22.

Control of the optical scanner 30 includes control of the scan range (scan start position and scan end position) and scan speed.

The control of the photographing optical system 40 includes the control of the moving mechanism 47D. The moving mechanism 47D moves the focusing lens 47 in the optical axis direction of the photographing optical system 40. The main control unit 101 can control the moving mechanism 47D based on the analysis results of the image acquired using the image sensor 51. The main control unit 101 can also control the moving mechanism 47D based on the operation contents of the user using the operation unit 110 described below.

The control of the imaging device 50 includes the control of the image sensor 51 (rolling shutter control). The control of the image sensor 51 includes reset control, exposure control, charge transfer control, output control, etc. In addition, it is possible to change the time Tr required for reset control, the time (exposure time) Te required for exposure control, the time Tc required for charge transfer control, the time Tout required for output control, etc.

The control of the data processing unit 200 includes various image processing and analysis processing of the light reception results obtained from the image sensor 51. The image processing includes noise removal processing of the light reception results, and brightness correction processing to make it easier to identify specific areas depicted in the light reception image based on the light reception results. The analysis processing includes processing to identify the focus state.

The data processing unit 200 is capable of forming a light reception image corresponding to any aperture range based on the light reception results read out from the image sensor 51 by the rolling shutter method under the control of the main control unit 101 (control unit 100). The data processing unit 200 is capable of sequentially forming light reception images corresponding to the aperture range, and forming an image of the subject's eye E from the multiple light reception images formed.

The data processing unit 200 includes a processor and performs processing according to programs stored in a storage unit or the like to realize the above functions.

(Memory unit 102)
The storage unit 102 stores various computer programs and data. The computer programs include a calculation program and a control program for controlling the ophthalmic apparatus 1.

(Operation Unit 110)
The operation unit 110 includes an operation device or an input device. The operation unit 110 includes buttons and switches (e.g., an operation handle, an operation knob, etc.) and operation devices (a mouse, a keyboard, etc.) provided on the ophthalmic apparatus 1. The operation unit 110 may also include any operation device or input device, such as a trackball, an operation panel, a switch, a button, or a dial.

(Display unit 120)
The display unit 120 displays the image of the subject's eye E generated by the data processing unit 200. The display unit 120 includes a display device such as a flat panel display such as a liquid crystal display (LCD). The display unit 120 may also include various display devices such as a touch panel provided on the housing of the ophthalmologic apparatus 1.

It should be noted that the operation unit 110 and the display unit 120 do not need to be configured as separate devices. For example, it is possible to use a device in which the display function and the operation function are integrated, such as a touch panel. In that case, the operation unit 110 is configured to include this touch panel and a computer program. The operation content for the operation unit 110 is input to the control unit 100 as an electrical signal. Furthermore, operations and information input may be performed using a graphical user interface (GUI) displayed on the display unit 120 and the operation unit 110. In some embodiments, the functions of the display unit 120 and the operation unit 110 are realized by a touch screen.

(Other configurations)
In some embodiments, the ophthalmic apparatus 1 further includes a fixation projection system. For example, the optical path of the fixation projection system is coupled to the optical path of the imaging optical system 40 in the optical system configuration shown in FIG. 1. The fixation projection system can present an internal fixation target or an external fixation target to the subject's eye E. When presenting an internal fixation target to the subject's eye E, the fixation projection system includes an LCD that displays the internal fixation target under the control of the control unit 100, and projects the fixation light beam output from the LCD onto the fundus of the subject's eye E. The LCD is configured to be able to change the display position of the fixation target on its screen. By changing the display position of the fixation target on the LCD, it is possible to change the projection position of the fixation target on the fundus of the subject's eye E. The display position of the fixation target on the LCD can be specified by the user using the operation unit 110.

In some embodiments, the ophthalmic device 1 includes an alignment system. In some embodiments, the alignment system includes an XY alignment system and a Z alignment system. The XY alignment system is used to align the device optical system and the subject's eye E in a direction intersecting the optical axis of the device optical system (objective lens 46). The Z alignment system is used to align the device optical system and the subject's eye E in the direction of the optical axis of the ophthalmic device 1 (objective lens 46).

For example, the XY alignment system projects a bright spot (a bright spot in the infrared or near-infrared region) onto the subject's eye E. The data processing unit 200 acquires an anterior segment image of the subject's eye E onto which the bright spot is projected, and determines the displacement between the bright spot image depicted in the acquired anterior segment image and the alignment reference position. The control unit 100 moves the device optical system and the subject's eye E relatively in a direction intersecting the direction of the optical axis using a movement mechanism (not shown) so that the determined displacement is cancelled.

For example, the Z alignment system projects alignment light in the infrared or near-infrared region from a position off the optical axis of the device optical system, and receives the alignment light reflected by the anterior segment of the subject's eye E. The data processing unit 200 determines the distance of the subject's eye E from the device optical system based on the receiving position of the alignment light, which changes depending on the distance of the subject's eye E from the device optical system. The control unit 100 moves the device optical system and the subject's eye E relatively in the direction of the optical axis using a movement mechanism (not shown) so that the determined distance becomes the desired working distance.

In some embodiments, the function of the alignment system is realized by two or more anterior segment cameras positioned off the optical axis of the device optical system. For example, as disclosed in JP 2013-248376 A, the data processing unit 200 analyzes anterior segment images of the subject eye E acquired substantially simultaneously by two or more anterior segment cameras, and identifies the three-dimensional position of the subject eye E using a known trigonometric method. The control unit 100 moves the device optical system and the subject eye E relative to each other in three dimensions using a movement mechanism (not shown) so that the optical axis of the device optical system approximately coincides with the axis of the subject eye E and the distance of the device optical system to the subject eye E is a predetermined working distance.

[Action]
Next, an example of the operation of the ophthalmologic apparatus 1 will be described.

FIG. 11 shows a flow diagram of an example of the operation of the ophthalmologic apparatus 1 according to the embodiment. The storage unit 102 stores a computer program for implementing the processing shown in FIG. 11. The main control unit 101 operates according to this computer program to execute the processing shown in FIG. 11.

In this case, it is assumed that the alignment of the device optical system with respect to the subject's eye E is completed by an alignment system (not shown), and a fixation target is projected onto the fundus of the subject's eye E so as to guide it to the desired fixation position by a fixation projection system (not shown).

(S1: Obtain refractive power)
First, the main controller 101 acquires the refractive power of the subject's eye E from an external ophthalmic measurement device or an electronic medical chart.

For example, the main control unit 101 acquires the refractive power of the subject eye E from an external ophthalmic measurement device or electronic medical record via a communication unit (not shown).

(S2: Change the position of the slit)
Next, the main controller 101 changes the position of the slit 22 on the optical axis of the illumination optical system 20 according to the refractive power of the subject's eye E acquired in step S1.

Specifically, the main control unit 101 refers to the first control information stored in the memory unit 102 to identify the position of the slit 22 corresponding to the refractive power, and controls the movement mechanism 22D so that the slit 22 is positioned at the identified position.

(S3: Illumination light is applied)
Next, the main controller 101 starts irradiating the desired irradiation range of the fundus Ef with the illumination light by generating slit-shaped illumination light using the illumination optical system 20 and starting deflection control of the optical scanner 30. When irradiation of the illumination light is started, the slit-shaped illumination light is sequentially irradiated within the desired irradiation range as described above.

(S4: Obtain light reception result)
As described above, the main controller 101 acquires the light reception results of the pixels in the aperture range of the image sensor 51 corresponding to the irradiation range of the illumination light on the fundus Ef executed in step S3.

(S5: Next irradiation position?)
The main controller 101 determines whether there is a next irradiation position to be irradiated with the illumination light. The main controller 101 can determine whether there is a next irradiation position to be irradiated with the illumination light by determining whether the irradiation range of the illumination light, which is sequentially moved, covers a predetermined photographing range of the fundus Ef.

When it is determined that there is a position to be irradiated with the illumination light next (S5: Y), the operation of the ophthalmic device 1 proceeds to step S3. When it is determined that there is no position to be irradiated with the illumination light next (S5: N), the operation of the ophthalmic device 1 proceeds to step S6.

(S6: Forming an image)
In step S5, when it is determined that there is no next irradiation position to be irradiated with the illumination light (S5: N), the main control unit 101 causes the data processing unit 200 to form an image of the test eye E from the light reception results repeatedly obtained while changing the irradiation range of the illumination light in step S4.

For example, the data processing unit 200 combines multiple light receiving results with different illumination light irradiation ranges (opening ranges on the light receiving surface SR of the image sensor 51) for the number of times the processes in steps S3 to S5 are repeated, based on the order in which the irradiation ranges move. This forms one frame of a fundus image of the fundus Ef.

In some embodiments, in step S3, illumination light is applied to an illumination range that is set so that an overlapping area with an adjacent illumination range is provided. As a result, in step S6, one frame of a fundus image is formed by combining the images so that the overlapping areas overlap each other.

This completes the operation of the ophthalmic device 1 (END).

As described above, in the first embodiment, the light sources 10A and 10B are arranged adjacent to each other in correspondence with the first opening 21A and the second opening 21B formed in the iris diaphragm 21. At this time, the center of the first opening 21A is arranged on the optical axis of the light source 10A, and the center of the second opening 21B is arranged on the optical axis of the light source 10B. In addition, each of the light sources 10A and 10B is arranged so that the diagonal direction of the approximately rectangular light-emitting area is approximately aligned with the longitudinal direction of the corresponding opening. This makes it possible to brightly illuminate the observation site with a simple configuration while suppressing the heat generation amount of each of the two or more light sources. In particular, by using a high-brightness light source that becomes more bright as the light-emitting area becomes smaller, the utilization efficiency of the light emission amount of the light source can be increased. For example, compared to the case where the light from the light source is magnified by a lens or the like and enlarged and projected onto the iris diaphragm, the longitudinal direction of the opening formed in the slit can be sufficiently illuminated. As a result, it is possible to increase the size of the illumination opening, increase the numerical aperture at the observation site, and observe the observation site more clearly.

Second Embodiment
The configuration of the ophthalmic apparatus according to the embodiment is not limited to the configuration according to the first embodiment. For example, each of two or more light sources that irradiate light to the iris diaphragm 21 may be disposed at a position that is approximately optically conjugate with a corresponding one of two or more openings formed in the iris diaphragm 21.

The following describes the ophthalmic device according to the second embodiment, focusing on the differences from the ophthalmic device 1 according to the first embodiment.

FIGS. 12 and 13 show an example of the configuration of an optical system of an ophthalmic apparatus according to the second embodiment. In FIG. 12, parts similar to those in FIG. 1 are given the same reference numerals, and descriptions thereof will be omitted where appropriate. FIG. 13 is a schematic diagram showing the configuration of the optical system of the illumination optical system 20a in FIG. 12 in the YZ plane. In FIG. 13, parts similar to those in FIG. 3 are given the same reference numerals, and descriptions thereof will be omitted where appropriate.

As shown in FIG. 12, the configuration of the ophthalmic device 1a according to the second embodiment differs from the configuration of the ophthalmic device 1 according to the first embodiment in that an illumination optical system 20a is provided instead of the illumination optical system 20. The illumination optical system 20a differs from the illumination optical system 20 in that a relay lens 11A, a reflecting member 12A, a relay lens 11B, and a reflecting member 12B are added.

In the second embodiment, similar to the first embodiment, a light source 10A is provided corresponding to a first opening 21A formed in the iris diaphragm 21, and a light source 10B is provided corresponding to a second opening 21B formed in the iris diaphragm 21. A relay lens 11A and a reflecting member 12A are disposed between the light source 10A and the first opening 21A. A relay lens 11B and a reflecting member 12B are disposed between the light source 10B and the second opening 21B. Each of the reflecting members 12A and 12B may be a reflecting mirror or a prism.

In the second embodiment, the light source 10A is configured to be disposed at a position that is approximately optically conjugate with the first opening 21A. The center of the first opening 21A is disposed on the optical axis of the light source 10A. The relay lens 11A transmits the light emitted from the light source 10A and guides it to the reflecting member 12A. The relay lens 11A includes one or more lenses. The reflecting member 12A deflects the light that has transmitted through the relay lens 11A and guides it to the first opening 21A.

Similarly, the light source 10B is configured to be positioned at a position that is approximately optically conjugate with the second opening 21B. The center of the second opening 21B is positioned on the optical axis of the light source 10B. The relay lens 11B transmits the light emitted from the light source 10B and guides it to the reflecting member 12B. The relay lens 11B includes one or more lenses. The reflecting member 12B deflects the light that has transmitted through the relay lens 11B and guides it to the second opening 21B.

In some embodiments, a relay lens 11A is disposed between the reflecting member 12A and the first opening 21A, and a relay lens 11B is disposed between the reflecting member 12B and the second opening 21B.

The operation of the ophthalmic device 1a according to the second embodiment is similar to that of the ophthalmic device 1 according to the first embodiment, and therefore will not be described.

As described above, according to the second embodiment, it is possible to improve the degree of freedom in the arrangement of the light sources 10A and 10B while achieving the same effects as the first embodiment. For example, even if the distance between the first opening 21A and the second opening 21B is narrow or the size of the light sources 10A and 10B is large, it is possible to improve the utilization efficiency of the amount of light emitted by the light sources.

Third Embodiment
The configuration of the ophthalmologic apparatus according to the embodiment is not limited to the configuration according to the embodiment described above. For example, the ophthalmologic apparatus may be configured such that light emitted from each of two or more light sources that irradiate the iris diaphragm 21 is guided to a corresponding one of two or more openings formed in the iris diaphragm 21 through a light guide member.

The following describes the ophthalmic device according to the third embodiment, focusing on the differences from the ophthalmic device 1 according to the first embodiment.

FIGS. 14 and 15 show an example of the configuration of an optical system of an ophthalmic apparatus according to the third embodiment. In FIG. 14, parts similar to those in FIG. 1 are given the same reference numerals, and descriptions thereof will be omitted where appropriate. FIG. 15 shows a schematic diagram of the configuration of the optical system of the illumination optical system 20b in FIG. 14 in the YZ plane. In FIG. 15, parts similar to those in FIG. 3 are given the same reference numerals, and descriptions thereof will be omitted where appropriate.

As shown in FIG. 14, the configuration of the ophthalmic device 1b according to the third embodiment differs from the configuration of the ophthalmic device 1 according to the first embodiment in that an illumination optical system 20b is provided instead of the illumination optical system 20. The illumination optical system 20b differs from the illumination optical system 20 in that a flexible light-guiding member 15A, a coupling lens 16A, a lens 17A, a flexible light-guiding member 15B, a coupling lens 16B, and a lens 17B are added.

In the third embodiment, similar to the first embodiment, a light source 10A is provided corresponding to a first opening 21A formed in the iris diaphragm 21, and a light source 10B is provided corresponding to a second opening 21B formed in the iris diaphragm 21. A coupling lens 16A, a light guide member 15A, and a lens 17A are disposed between the light source 10A and the first opening 21A. A coupling lens 16B, a light guide member 15B, and a lens 17B are disposed between the light source 10B and the second opening 21B.

Each of the coupling lenses 16A, 16B may be a cylindrical lens or a toric lens. An example of the light-guiding members 15A, 15B is an optical fiber. In this case, the optical fiber may be a bundle type configured to change the shape (cross-sectional shape of the light beam) and NA of the emitted light, or a tapered type with different NA or core systems on the entrance and exit sides. Hereinafter, each of the light-guiding members 15A, 15B is considered to be a bundle type optical fiber configured to change the shape of the emitted light to match the shape of the opening formed in the iris diaphragm 21.

If the focal length of the coupling lens 16A is fcpl, the incident end of the light-guiding member 15A is disposed at the rear focal position of the coupling lens 16A. For example, the exit end of the light-guiding member 15A is disposed at a position that is approximately optically conjugate with the first opening 21A. The lens 17A is disposed between the exit end of the light-guiding member 15A and the first opening 21A. The lens 17A includes one or more lenses. In some embodiments, the lens 17A is a relay lens.

Similarly, if the focal length of coupling lens 16B is fcpl, the incident end of light-guiding member 15B is disposed at the rear focal position of coupling lens 16B. For example, the exit end of light-guiding member 15B is disposed at a position that is approximately optically conjugate with second opening 21B. Lens 17B is disposed between the exit end of light-guiding member 15B and second opening 21B. Lens 17B includes one or more lenses. In some embodiments, lens 17B is a relay lens.

In the third embodiment, the center of the first opening 21A is also located on the optical axis of the light source 10A, and the center of the second opening 21B is also located on the optical axis of the light source 10B.

In the third embodiment, light from light source 10A is focused by coupling lens 16A at the incident end of light-guiding member 15A. Light-guiding member 15A emits light incident on the incident end from the emission end. The light emitted from the emission end of light-guiding member 15A is refracted by lens 17A so as to pass through first opening 21A. Light from light source 10B is focused by coupling lens 16B at the incident end of light-guiding member 15B. Light-guiding member 15B emits light incident on the incident end from the emission end. The light emitted from the emission end of light-guiding member 15B is refracted by lens 17B so as to pass through second opening 21B.

The operation of the ophthalmic device 1b according to the third embodiment is similar to that of the ophthalmic device 1 according to the first embodiment, and therefore will not be described.

As described above, according to the third embodiment, it is possible to improve the degree of freedom in arranging the light sources 10A, 10B relative to the opening formed in the iris diaphragm 21 while achieving the same effects as the first embodiment. For example, the light sources 10A, 10B can be arranged at a position away from the opening formed in the iris diaphragm 21. This makes it possible to improve the efficiency of use of the amount of light emitted by the light sources even when the distance between the first opening 21A and the second opening 21B is narrow or when the sizes of the light sources 10A, 10B are large.

[Action]
An ophthalmic apparatus according to an embodiment will be described.

A first aspect of some embodiments is an ophthalmic device (1, 1a, 1b) including two or more light sources (light sources 10A, 10B), an illumination optical system (20, 20a, 20b), a light receiving optical system (photographing optical system 40), and an optical path splitting member (hole mirror 45). The illumination optical system includes an iris diaphragm and an illumination diaphragm (slit 22), and illuminates the test eye (E) with light from two or more light sources through the iris diaphragm and the illumination diaphragm. The iris diaphragm is disposed at an iris conjugate position (Q) that is approximately optically conjugate with the iris of the test eye, and two or more openings (first opening 21A, second opening 21B) are formed. The illumination diaphragm is disposed at a fundus conjugate position (P) that is approximately optically conjugate with the fundus (Ef) of the test eye. The light receiving optical system guides the return light from the test eye to an imaging element (image sensor 51). The optical path splitting member spatially splits the optical path of the illumination optical system and the optical path of the light receiving optical system so that the images of the two or more apertures are arranged around the light receiving aperture through which the return light passes on the plane at the iris conjugate position. The centers of the two or more apertures corresponding to each other are arranged on the optical axes of the two or more light sources.

According to this embodiment, it is possible to brightly illuminate the observation area with a simple configuration while suppressing the amount of heat generated by each of the two or more light sources. In particular, by using a high-brightness light source that becomes brighter as the light-emitting area becomes smaller, the efficiency of using the amount of light emitted by the light source can be improved.

In a second aspect of some embodiments, in the first aspect, the optical axis of the light source is an optical axis that passes through the center of the light-emitting area of the light source.

This type of configuration makes it possible to use light emitted from the center of the light-emitting region, improving the efficiency of use of the amount of light emitted by the light source.

In a third aspect of some embodiments, in the second aspect, the diagonal direction of the light-emitting region substantially coincides with the longitudinal direction of the corresponding opening.

According to this embodiment, even if one side of the light emitting area of the light source is shorter than the length of the opening formed in the iris diaphragm, it is possible to improve the efficiency of use of the amount of light emitted by the light source.

In a fourth aspect of some embodiments, in any of the first to third aspects, each of the two or more light sources is disposed at a position that is approximately optically conjugate with a corresponding one of the two or more apertures.

This aspect allows for greater freedom in arranging the light source. For example, even when the spacing between two or more openings formed in the iris diaphragm is narrow or when the size of the light source is large, it is possible to improve the efficiency of use of the amount of light emitted by the light source.

A fifth aspect of some embodiments is any of the first to third aspects, including two or more light-guiding members (15A, 15B) that guide the light emitted from each of the two or more light sources to a corresponding one of the two or more openings.

This aspect allows for greater freedom in positioning the light source relative to the opening formed in the iris diaphragm. For example, the light source can be positioned away from the opening formed in the iris diaphragm.

A sixth aspect of some embodiments is the fifth aspect, which includes two or more lenses (coupling lenses 16A, 16B) arranged between each of the two or more light sources and each of the two or more light guiding members. The incident ends of the two or more light guiding members into which the emitted light is incident are arranged at the rear focal positions of each of the two or more lenses.

In this embodiment, the light guide member can reliably guide the light from the light source to the opening formed in the iris diaphragm, greatly improving the efficiency of use of the amount of light emitted by the light source.

In a seventh aspect of some embodiments, in the fifth aspect, the exit end of the emitted light guided by the light-guiding member is positioned at a position that is approximately optically conjugate with the corresponding opening.

In this embodiment, the light guide member can reliably guide the light from the light source to the opening formed in the iris diaphragm, greatly improving the efficiency of use of the amount of light emitted by the light source.

In an eighth aspect of some embodiments, in any of the first to third aspects, two openings are formed in the iris diaphragm. A position corresponding to the optical axis of the illumination optical system is located on a straight line connecting the centers of the two openings.

This aspect makes it possible to perform pupil division with a simple configuration while improving the efficiency of use of the amount of light emitted by the light source.

In a ninth aspect of some embodiments, in any of the first to third aspects, the iris diaphragm is formed with two or more openings (first opening 21A, second opening 21B) having an arch shape centered on the optical axis of the illumination optical system.

This aspect makes it possible to perform pupil division with a simple configuration while improving the efficiency of use of the amount of light emitted by the light source.

A tenth aspect of some embodiments includes an optical scanner (30) that deflects the light that has passed through the illumination aperture in the first to third aspects and guides the deflected illumination light to the fundus. The light reception result of the return light obtained by the imaging element is captured in synchronization with the deflection control of the optical scanner.

This aspect makes it possible to obtain high-quality fundus images with a simple configuration without being affected by unnecessary illumination light.

In an eleventh aspect of some embodiments, in the tenth aspect, the imaging element is a rolling shutter type image sensor (51).

This aspect makes it possible to obtain high-quality fundus images with simple control, without being affected by unnecessary illumination light.

A twelfth aspect of some embodiments is any of the first to third aspects, which includes a movement mechanism (22D) that moves the illumination diaphragm in the optical axis direction according to the state of the subject's eye.

This aspect makes it possible to obtain high-quality fundus images without being affected by unnecessary illumination light, regardless of the condition of the subject's eye.

The above-described embodiment or its variations are merely examples of how to implement this invention. Anyone who wishes to implement this invention may make any modifications, omissions, additions, etc. within the scope of the gist of this invention.

In the above embodiment, the ophthalmic device may have any function that can be used in the field of ophthalmology, such as an axial length measurement function, an intraocular pressure measurement function, an optical coherence tomography (OCT) function, and an ultrasound examination function. The axial length measurement function may be realized by an optical coherence tomograph or the like. The axial length measurement function may measure the axial length of the subject eye by projecting light onto the subject eye and detecting the returning light from the fundus while adjusting the position of the optical system in the Z direction (front-back direction) relative to the subject eye. The intraocular pressure measurement function is realized by a tonometer or the like. The OCT function is realized by an optical coherence tomograph or the like. The ultrasound examination function is realized by an ultrasound diagnostic device or the like. The present invention may also be applied to a device (multifunction device) equipped with two or more of these functions.

In some embodiments, a program is provided for causing a computer to execute the above-mentioned method for controlling an ophthalmic device. Such a program can be stored in any non-transitory recording medium that is readable by a computer. Examples of such recording media include semiconductor memory, optical disks, magneto-optical disks (CD-ROM/DVD-RAM/DVD-ROM/MO, etc.), and magnetic storage media (hard disks/floppy disks/ZIP, etc.). It is also possible to transmit and receive the program via a network such as the Internet or a LAN.

Reference Signs List 1, 1a, 1b Ophthalmic apparatus 10A, 10B Light source 11A, 11B Relay lens 12A, 12B Reflecting member 15A, 15B Light guide member 16A, 16B Coupling lens 17A, 17B Lens 20, 20a, 20b Illumination optical system 21 Iris diaphragm 21A First opening 21B Second opening 22 Slit 23 Condenser lens 30 Optical scanner 35 Projection optical system 40 Photography optical system 45 Hole mirror 46 Objective lens 50 Imaging device 51 Image sensor E Eye to be examined Ef Fundus

Claims (12)

Two or more light sources;
an illumination optical system including an iris diaphragm arranged at an iris conjugate position that is optically conjugate with an iris of a subject's eye and having two or more openings formed therein, and an illumination diaphragm arranged at a fundus conjugate position that is optically conjugate with a fundus of the subject's eye, the illumination optical system illuminating the subject's eye with light from the two or more light sources via the iris diaphragm and the illumination diaphragm;
a light receiving optical system that guides return light from the subject's eye to an image sensor;
an optical path splitting member that spatially splits an optical path of the illumination optical system and an optical path of the light receiving optical system so that images of the two or more apertures are disposed around a light receiving aperture through which the return light passes on a plane at the iris conjugate position;
Including,
An ophthalmic device, wherein the centers of corresponding openings among the two or more apertures are located on the optical axes of the two or more light sources. The ophthalmic apparatus according to claim 1 , wherein an optical axis of the light source passes through a center of a light-emitting area of the light source. The ophthalmic device according to claim 2 , wherein a diagonal direction of the light emitting region substantially coincides with a longitudinal direction of the corresponding opening. The ophthalmic apparatus according to any one of claims 1 to 3, characterized in that each of the two or more light sources is disposed at a position that is approximately optically conjugate with a corresponding one of the two or more apertures. The ophthalmic apparatus according to any one of claims 1 to 3, further comprising two or more light guiding members that guide the light emitted from each of the two or more light sources to a corresponding one of the two or more openings. two or more lenses disposed between each of the two or more light sources and each of the two or more light guiding members;
The ophthalmic apparatus according to claim 5 , wherein an incident end of each of the two or more light guiding members onto which the emitted light is incident is disposed at a rear focal position of each of the two or more lenses. The ophthalmic apparatus according to claim 5 , wherein an exit end of the exit light guided by the light guide member is disposed at a position that is optically conjugate with the corresponding opening. The iris diaphragm has two openings formed therein,
4. The ophthalmic apparatus according to claim 1, wherein a position corresponding to an optical axis of the illumination optical system is located on a straight line connecting the centers of the two openings. 4. The ophthalmic apparatus according to claim 1, wherein the iris diaphragm has two or more openings formed therein, each opening having an arch shape centered on an optical axis of the illumination optical system. an optical scanner that deflects light that has passed through the illumination aperture and guides the deflected illumination light to the fundus;
4. The ophthalmic apparatus according to claim 1, further comprising: a light receiving result of the return light obtained by the image sensor, which is acquired in synchronization with a deflection control of the optical scanner. The ophthalmologic apparatus according to claim 10 , wherein the imaging element is a rolling shutter type image sensor. 4. The ophthalmic apparatus according to claim 1, further comprising a moving mechanism for moving the illumination diaphragm in an optical axis direction in accordance with a state of the subject's eye.

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