Optical scanning device

Abstract

This invention provides a new technology for low-cost correction of two or more aberrations when rapidly scanning the peripheral areas of measurement sites, which vary depending on the object being measured. [Solution] The optical scanning device is configured to irradiate a measurement area on the object to be measured with light and to receive the reflected light from the measurement area. The optical scanning device includes a first aberration correction optical system, a second aberration correction optical system, and a scanning optical system. The first aberration correction optical system forms a first image having a first aberration at a position optically substantially conjugate to the measurement area by scanning light, and descans the light that forms the first image. The second aberration correction optical system forms a second image having a second aberration different from the first aberration at a position optically substantially conjugate to the measurement area by scanning the light from the first aberration correction optical system, and descans the light that forms the second image. The scanning optical system deflects the light descanned by the second aberration correction optical system and guides it to the object to be measured.

Description

[Technical Field]

[0001] The present disclosure relates to an optical scanning device. [Background Art]

[0002] An optical scanning device capable of measuring (imaging) a measurement site on an object to be measured by irradiating the measurement site with light and receiving the returned light is affected by aberrations such as field curvature and astigmatism, resulting in reduced measurement accuracy.

[0003] When the measurement site of the object to be measured has a curved shape, the influence of off-axis aberration around the measurement site increases, and the measurement accuracy of a site distant from the measurement optical axis decreases. For example, when the object to be measured is an eye to be examined, it is known that axial lengths vary among individuals, and the shape of the peripheral portion of the fundus, which has a curved cross-sectional shape, exhibits large variations. Furthermore, it is known that the degree of astigmatism varies among individuals, and variations in astigmatism also increase in the peripheral region of the fundus. As a result, during wide-angle measurement of the fundus, the influence of off-axis aberration corresponding to the eye to be examined increases, leading to reduced measurement accuracy depending on the individual eye to be examined.

[0004] Such off-axis aberration can be corrected by using an adaptive optics system including a wavefront sensor and a deformable mirror when the measurement device employs a scanning optical system. However, adaptive optics systems are expensive.

[0005] On the other hand, off-axis aberration can be corrected by performing focus adjustment and astigmatism adjustment on the peripheral portion of the fundus. However, with this method, when scanning the fundus at high speed, it is difficult to make focus adjustment and astigmatism adjustment follow the high scanning speed.

[0006] Patent Document 1 discloses a method for correcting chromatic aberration using a Gaussian lens. Patent Document 2 discloses a method for correcting astigmatism using a slit mirror. Patent Document 3 discloses a method for correcting aberrations by dividing the pupil into multiple sub-apers. Patent Document 4 discloses a method for pre-compensating for laser beam aberrations using a combination of an XY scanner and a Z scanner. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 06-337348 [Patent Document 2] Special Publication No. 2009-543585 [Patent Document 3] Special Publication No. 2017-522066 [Patent Document 4] Special Publication No. 2013-500130 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] However, conventional methods cannot correct for two or more aberrations at low cost when rapidly scanning the peripheral areas of measurement points that differ depending on the object being measured.

[0009] This invention has been made in view of the above circumstances, and one of its objectives is to provide a new technique for correcting two or more types of aberrations at low cost when rapidly scanning the peripheral areas of measurement sites which differ depending on the object being measured. [Means for solving the problem]

[0010] One embodiment of the optical scanning device is configured to irradiate a measurement site on an object to be measured with light and receive reflected light from the measurement site. The optical scanning device includes a first aberration correction optical system, a second aberration correction optical system, and a scanning optical system. The first aberration correction optical system forms a first image having a first aberration at a position approximately conjugate to the measurement site by scanning light, and descans the light forming the first image. The second aberration correction optical system forms a second image having a second aberration different from the first aberration at a position approximately conjugate to the measurement site by scanning light from the first aberration correction optical system, and descans the light forming the second image. The scanning optical system deflects the light descanned by the second aberration correction optical system and guides it to the object to be measured. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a new technique for correcting two or more types of aberrations at low cost when rapidly scanning the peripheral areas of measurement sites which differ depending on the object being measured. [Brief explanation of the drawing]

[0012] [Figure 1] This is a schematic diagram showing an example of the configuration of the optical system of an ophthalmic device according to the embodiment. [Figure 2] This is a schematic diagram showing an example of the configuration of the optical system of an ophthalmic device according to the embodiment. [Figure 3A] This is an explanatory diagram of the optical system of an ophthalmic device according to an embodiment. [Figure 3B] This is an explanatory diagram of the optical system of an ophthalmic device according to an embodiment. [Figure 4A] This is an explanatory diagram of the optical system of an ophthalmic device according to an embodiment. [Figure 4B] This is an explanatory diagram of the optical system of an ophthalmic device according to an embodiment. [Figure 5] This is an explanatory diagram of the optical system of an ophthalmic device according to an embodiment. [Figure 6] This is an explanatory diagram of the optical system of an ophthalmic device according to an embodiment. [Figure 7] This is a schematic diagram showing an example of the configuration of the control system of an ophthalmic device according to the embodiment. [Figure 8] It is an explanatory diagram for explaining the operation of the ophthalmologic apparatus according to the embodiment. [Figure 9] It is an explanatory diagram for explaining the operation of the ophthalmologic apparatus according to the embodiment. [Figure 10] It is an explanatory diagram for explaining the operation of the ophthalmologic apparatus according to the embodiment. [Figure 11] It is an explanatory diagram for explaining the operation of the ophthalmologic apparatus according to the embodiment. [Figure 12] It is an explanatory diagram for explaining the operation of the ophthalmologic apparatus according to the embodiment. [Figure 13] It is an explanatory diagram for explaining the operation of the ophthalmologic apparatus according to the embodiment. [Figure 14] It is a flowchart showing an example of the operation of the ophthalmologic apparatus according to the embodiment. [Figure 15A] It is a flowchart showing an example of the operation of the ophthalmologic apparatus according to the embodiment. [Figure 15B] It is a flowchart showing an example of the operation of the ophthalmologic apparatus according to the embodiment. [Figure 16A] It is an explanatory diagram for explaining the operation of the ophthalmologic apparatus according to the embodiment. [Figure 16B] It is an explanatory diagram for explaining the operation of the ophthalmologic apparatus according to the embodiment. [Figure 17] It is a schematic diagram showing an example of the configuration of an optical system of an ophthalmologic apparatus according to a first modification of the embodiment. [Figure 18] It is a schematic diagram showing an example of the configuration of an optical system of an ophthalmologic apparatus according to a second modification of the embodiment. [Figure 19] It is a schematic diagram showing an example of the configuration of an optical system of an ophthalmologic apparatus according to a third modification of the embodiment. [Figure 20] It is a schematic diagram showing an example of the configuration of an optical system of an ophthalmologic apparatus according to a fourth modification of the embodiment. DESCRIPTION OF EMBODIMENTS

[0013] An example of an embodiment of the optical scanning device according to this invention will be described in detail with reference to the drawings. It should be noted that the contents of the documents cited in this specification and any prior art can be incorporated into the following embodiments.

[0014] The optical scanning device according to this embodiment is configured to irradiate a measurement area on the object to be measured with light at a wide angle and to receive the reflected light from the measurement area.

[0015] The optical scanning device includes two or more aberration correction optical systems and a scanning optical system. Each of the two or more aberration correction optical systems corresponds to each of two or more different types of aberrations.

[0016] Each aberration correction optical system is configured to scan (deflect) incident light to form an image with aberrations that cancel out the aberrations of the preceding (light source side) or succeeding (object under measurement side) optical system, at a position that is optically substantially conjugate to the measurement site. Each aberration correction optical system is configured to descan the light from the formed image and output it to the next aberration correction optical system or scanning optical system. Two or more aberration correction optical systems are connected in series. In some embodiments, all two or more aberration correction optical systems have the same configuration. In some embodiments, at least one of the two or more aberration correction optical systems has a different configuration from the other aberration correction optical systems.

[0017] The scanning optical system is configured to deflect the light emitted from the final aberration correction optical system among two or more aberration correction optical systems and guide it towards the object to be measured.

[0018] In other words, each aberration correction optical system forms an image (image plane) with aberrations according to the deflection angle of the incident light, descans the light from the formed image, and directs the descanned light into the next stage aberration correction optical system. An image is formed as described above for each type of aberration, the light from the formed image is descanned, and the light from the final stage aberration correction optical system is deflected by a scanning optical system.

[0019] This allows for the adjustment of the incident light deflection angle according to the object being measured, making it possible to compensate for different types of aberrations depending on the object being measured. By employing a scanner with specifications similar to those used in scanning optical systems for incident light deflection, it becomes possible to compensate for two or more different types of aberrations depending on the object being measured at low cost while keeping up with the high scanning speed of the measurement area. In some embodiments, a single type of aberration is corrected using two or more aberration correction optical systems.

[0020] The optical scanning apparatus according to this embodiment includes at least two aberration correction optical systems. The two aberration correction optical systems are a first aberration correction optical system and a second aberration correction optical system. The first aberration correction optical system scans the light irradiated onto the measurement area to form a first image (first image plane) having a first aberration at a position approximately conjugate to the measurement area, and descans the light forming the first image. The second aberration correction optical system scans the light descanned by the first aberration correction optical system again to form a second image (second image plane) having a second aberration different from the first aberration at a position approximately conjugate to the measurement area, and descans the light forming the second image. The scanning optical system deflects the light descanned by the second aberration correction optical system and guides it to the measurement area of ​​the object to be measured.

[0021] In each aberration-correcting optical system, the descan of light from the image is performed in synchronization with the scanning of the incident light. The scanning of light in each aberration-correcting optical system is either a uniaxial scan in one direction or a biaxial scan in two directions, depending on the type of aberration to be compensated for. Similarly, the descan of light in each aberration-correcting optical system is either a uniaxial descan in one direction or a biaxial descan in two directions, depending on the type of aberration to be compensated for.

[0022] In some embodiments, the first aberration correction optical system or the second aberration correction optical system includes a first deflection member, a second deflection member, and a relay optical system disposed between the first and second deflection members. The optical scanning device is configured to use the first deflection member to scan the light illuminating the measurement area and guide it to the relay optical system, thereby forming an aberration-affected image at a position approximately conjugate to the measurement area, and to use the second deflection member to descan the light passing through the relay optical system.

[0023] In this case, the first deflection member may be a uniaxial scanner or a biaxial scanner. The second deflection member may be a uniaxial scanner or a biaxial scanner. In some embodiments, the system is configured to perform scanning by the first scanner and descanning by the second scanner in synchronization with the light deflection operation of the scanning optical system.

[0024] In some embodiments, the first aberration correction optical system or the second aberration correction optical system includes a scanner having a first deflection member and a second deflection member, and a relay optical system. The relay optical system includes one or more reflective members that are positioned between the first deflection member and the second deflection member and are deflected by the first deflection member, and that reflect light illuminating the measurement site. In this case, the optical scanning device is configured to use the first deflection member to scan the light illuminating the measurement site and guide it to the relay optical system, thereby forming an aberration-affected image at a position approximately conjugate to the measurement site, and to use the second deflection member to descan the light passing through the relay optical system.

[0025] In some embodiments, the scanner includes a substrate. In this case, the first deflection member is provided on the first surface of the substrate, and the second deflection member is provided on the second surface, which is the back surface of the first surface of the substrate.

[0026] In some embodiments, the deflection surface of the first deflection member and the deflection surface of the second deflection member are positioned in substantially conjugate optical positions.

[0027] The relay optical system includes one or more lenses. In some embodiments, the relay optical system is a double Gauss lens including a pair of lens groups having optical symmetry in the optical axis direction. In this case, the first lens group and the second lens group constituting the pair of lens groups may each have the same power.

[0028] In some embodiments, the first aberration correction optical system and the second aberration correction optical system (two or more off-axis aberration correction optical systems) are arranged in the optical path of the optical system (non-scanning optical system) between the light source that generates the light illuminating the eye under examination and the scanning optical system.

[0029] Examples of aberrations include off-axis aberrations. Examples of off-axis aberrations include third-order and higher-order aberrations (third-order aberration, fifth-order aberration, seventh-order aberration, ...). Examples of third-order aberrations include coma, field curvature, astigmatism, and distortion. Examples of fifth-order aberrations include annular coma, annular coma, peripheral astigmatism, and peripheral spherical field curvature. The following embodiments can also be applied to aberrations other than off-axis aberrations.

[0030] The following description will focus on the case where the optical scanning device according to the embodiment is an ophthalmic device that measures the eye as the object to be measured. However, the configuration according to the embodiment is not limited to this. The following embodiments can also be applied to devices that measure (photograph) objects other than the eye as the object to be measured.

[0031] Examples of measurement sites include the fundus, vitreous humor, and anterior segment of the eye. Examples of anterior segment sites include the cornea, iris, and iridocorneal angle.

[0032] Examples of ophthalmic devices according to this embodiment include optical coherence tomography (OCT), scanning laser ophthalmoscopy (SLO), and slit-scan type ophthalmic imaging devices.

[0033] An optical coherence tomography (OCT) system includes an interference optical system. The interference optical system is configured to split light from a light source into a measurement light and a reference light, guide the measurement light to the measurement site of the eye under examination, and generate interference light between the reference light passing through the reference light path and the return light of the measurement light from the measurement site, and to detect the generated interference light. In this case, the measurement light emitted from the interference optical system is deflected by a scanning optical system and irradiated onto the measurement site of the eye under examination. The optical coherence tomography system may be of the time domain OCT (TD-OCT), spectral domain OCT (SD-OCT), or swept source OCT (SS-OCT) type.

[0034] A scanning laser ophthalmoscope is configured to deflect laser light from a light source, guide the deflected laser light to the measurement site of the eye being examined, and detect the reflected laser light from the measurement site.

[0035] A slit-scan ophthalmic imaging device is configured to deflect a slit-shaped illumination beam, guide the deflected illumination beam to the measurement site of the eye being examined, and detect the reflected light from the measurement site. In this case, the effect of unwanted light can be reduced by moving the light-receiving area on the light-receiving surface in synchronization with the movement of the illumination area at the measurement site due to the deflection.

[0036] The control method for the ophthalmic apparatus according to the embodiment includes one or more steps for realizing processing performed by a processor (computer) in the ophthalmic apparatus according to the embodiment. The program according to the embodiment causes the processor to execute each step of the control method for the ophthalmic apparatus according to the embodiment. That is, the program according to the embodiment is a computer program that includes instructions for the computer to execute the control method for the ophthalmic apparatus according to the embodiment when the program is executed by the computer. The recording medium (storage medium) according to the embodiment is any non-transitory recording medium that is readable by a computer and on which the program according to the embodiment is recorded (stored). The recording medium may be an electronic medium that utilizes magnetism, light, magneto-optical technology, semiconductors, etc. Typically, recording media include magnetic tapes, magnetic disks, optical disks, magneto-optical disks, flash memory, solid-state drives, etc. Examples of magnetic disks include hard disks, floppy disks, ZIP and other magnetic storage media. Examples of magneto-optical disks include CD-ROMs, DVD-RAMs, DVD-ROMs, MOs, etc. It is also possible to send and receive this program via a network such as the Internet or a LAN.

[0037] In this specification, "processor" means, for example, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), an ASIC (Application Specific Integrated Circuit), a programmable logic device (e.g., SPLD (Simple Programmable Logic Device), CPLD (Complex Programmable Logic Device), FPGA (Field Programmable Gate Array)), or other circuit. The processor realizes the functions according to the embodiment by, for example, reading and executing a program stored in a memory circuit or memory device.

[0038] Hereinafter, the ophthalmic device according to the embodiment will be described as having the function of an SS-OCT type optical coherence tomography (OCT) meter. However, the configuration according to the embodiment is not limited thereto. The following embodiments can also be applied when the ophthalmic device has the function of an optical coherence tomography meter of a type other than the SS-OCT type, a scanning laser ophthalmoscope, or a slit-scan type ophthalmic imaging device.

[0039] Furthermore, the measurement site in the embodiment will be described as the fundus of the eye. However, the configuration in the embodiment is not limited thereto. The following embodiments can also be applied when the measurement site is a site other than the fundus of the eye.

[0040] Furthermore, the following embodiments describe a case in which the ophthalmic apparatus according to the embodiment includes a first off-axis aberration correction optical system and a second off-axis aberration correction optical system, and corrects field curvature and astigmatism (or coma aberration) as off-axis aberrations. However, the configuration according to the embodiment is not limited thereto. The following embodiments can be applied to any two combinations of third-order aberrations or aberrations of third order or higher, other than the combination of field curvature and astigmatism. Also, the following embodiments can be applied when the ophthalmic apparatus according to the embodiment includes three or more off-axis aberration correction optical systems.

[0041] In this specification, "a position approximately optically conjugate to the fundus of the eye under examination" means a position that is optically conjugate to the fundus of the eye under examination, or a position near a position that is optically conjugate to the fundus of the eye under examination. "A position approximately optically conjugate to the pupil (iris) of the eye under examination" means a position that is optically conjugate to the pupil (iris) of the eye under examination, or a position near a position that is optically conjugate to the pupil (iris) of the eye under examination. Hereafter, unless otherwise specified, a position approximately optically conjugate to the fundus of the eye under examination will be denoted as the fundus conjugate position P. Similarly, a position approximately optically conjugate to the pupil of the eye under examination will be denoted as the pupil conjugate position Q.

[0042] <Optical system> Figure 1 shows an example of the optical system configuration of an ophthalmic device according to an embodiment.

[0043] The ophthalmic apparatus 1 according to this embodiment includes an interference optical system 10, a collimator lens 20, an optical path length correction unit 30, a first off-axis aberration correction optical system 40, a second off-axis aberration correction optical system 41, a focusing optical system 50, an optical scanner 60 as a scanning optical system, and an objective optical system 70.

[0044] (Interferometric optics system 10) Figure 2 shows an example configuration of the interference optical system 10 in Figure 1. In Figure 2, as in Figure 1, the fundus conjugate position P is indicated.

[0045] The interference optical system 10 includes a wavelength-swept light source 11, fiber couplers 12 and 13, and a detector 14.

[0046] The wavelength-swept light source 11 changes the wavelength of the emitted light (light source) over time in the near-infrared wavelength band, which is invisible to the human eye. For example, the wavelength-swept light source 11 includes a laser light source that includes a resonator. The light source L0 emitted by the wavelength-swept light source 11 is guided to the fiber coupler 12 through the optical fiber f1.

[0047] The fiber coupler 12, for example, splits the light source L0 into a measurement light LS and a reference light LR with a branching ratio of 50:50. The measurement light LS is guided by an optical fiber f2, exits from the fiber end fe, and is led to the collimator lens 20 shown in Figure 1. The fiber end fe of the optical fiber f2 is positioned at the fundus conjugate position P. The measurement light LS exiting the collimator lens 20 is led to the eye under examination E, as described later, and enters the eye through the pupil Ep.

[0048] The measurement light LS entering the eye is scattered (including reflected) at various depths in the fundus Ef. The backscattered light of the measurement light LS due to the fundus Ef travels in the reverse direction along the same path as the forward path as the return light of the measurement light LS, and is guided to the fiber coupler 12, and then reaches the fiber coupler 13 through the optical fiber f4.

[0049] The fiber coupler 13 combines (interferes with) the return light of the measurement light LS from the fundus Ef and the reference light LR that is split by the fiber coupler 12 and passes through the optical fiber f3 as a reference optical path to generate interference light LC.

[0050] In some embodiments, the interference optical system 10 includes an optical element positioned in the reference optical path that can change the optical path length of the reference light LR. An example of such an optical element is a retroreflector.

[0051] The fiber coupler 13 generates a pair of interference rays LC by splitting the measurement light LS and the reference light LR at a predetermined splitting ratio (e.g., 50:50). The pair of interference rays LC emitted from the fiber coupler 13 are led to the detector 14 by optical fibers f5 and f6.

[0052] The detector 14 is, for example, a balanced photodiode having a pair of photodetectors that detect a pair of interferometric LCs, and outputting the difference between the detection results. The detector 14 supplies its detection result (detection signal) as an interferogram signal to the DAQ (Data Acquisition Board) described later. In some embodiments, the interference optical system 10 includes the detector 14.

[0053] The DAQ acquires the interferogram signal after A / D conversion by performing A / D conversion on the interferogram signal at a predetermined sampling frequency. At this time, the DAQ acquires the interferogram signal at a sampling timing synchronized with the k-clock signal corresponding to the wavelength sweep timing of the wavelength-swept light source 11.

[0054] (Collimator lens 20) The collimator lens 20 collimates (converts into parallel light) the measurement light LS emitted from the fiber end fe of the optical fiber f2 of the interference optical system 10. For example, the fiber end fe is positioned at the focal point of the collimator lens 20.

[0055] (Optical path length correction section 30) The optical path length correction unit 30 changes the optical path length of the measurement light LS emitted from the collimator lens 20. For example, the optical path length correction unit 30 includes a retroreflector. By relatively changing the optical path length of the reference light LR and the optical path length of the measurement light LS, it is possible to change the coherence gate position. In some embodiments, without placing the optical path length correction unit 30 in the optical path of the measurement light LS, the optical path length of the reference light LR is changed by an optical element placed in the reference optical path, as described above, thereby relatively changing the optical path length of the reference light LR and the optical path length of the measurement light LS.

[0056] The measurement light LS passing through the optical path length correction unit 30 is guided to the first off-axis aberration correction optical system 40.

[0057] (First off-axis aberration correction optical system 40) The first off-axis aberration correction optical system 40 deflects the measurement light LS and irradiates it onto the lens, thereby forming an image with off-axis aberrations that cancels out off-axis aberrations in the optical system in front of (light source side) or behind (eye side) the lens at the fundus conjugate position P. Furthermore, the first off-axis aberration correction optical system 40 performs a descan operation corresponding to the scanning operation on the measurement light LS, descanning the light from the above image and guiding it as focused light to the second off-axis aberration correction optical system 41.

[0058] As shown in Figure 3A or Figure 4A, the first off-axis aberration correction optical system 40 includes a first off-axis aberration scanner 401, a relay optical system 403, and a second off-axis aberration scanner 402. The first off-axis aberration scanner 401 (deflection plane) and the second off-axis aberration scanner 402 (deflection plane) are positioned at or near optically conjugate positions (i.e., optically approximately conjugate positions) relative to each other. Inside the relay optical system 403 is the fundus conjugate position P. Here, for the sake of explanation, the fundus conjugate position P is assumed to be a single real image, but it may be multiple real images or multiple virtual images.

[0059] In some embodiments, the first off-axis aberration scanner 401 (deflection surface) and the second off-axis aberration scanner 402 (deflection surface) are positioned at the pupillary conjugate position Q.

[0060] The first off-axis aberration scanner 401 and the second off-axis aberration scanner 402 perform deflection operations in sync with each other. More specifically, the first off-axis aberration scanner 401 and the second off-axis aberration scanner 402 perform deflection operations in sync with the deflection operation of the optical scanner 60, which will be described later.

[0061] In this embodiment, the off-axis aberration to be compensated for in the first off-axis aberration correction optical system 40 is image field curvature. In this case, the first off-axis aberration scanner 401 and the second off-axis aberration scanner 402 are each uniaxial scanners. In some embodiments, the first off-axis aberration scanner 401 and the second off-axis aberration scanner 402 are each biaxial scanners.

[0062] Furthermore, if the off-axis aberration to be compensated is a third-order aberration other than field curvature (coma aberration, astigmatism, or distortion aberration), or an aberration of a higher order than third order, then the first off-axis aberration scanner 401 and the second off-axis aberration scanner 402 are both dual-axis scanners.

[0063] The relay optical system 403 includes one or more lenses. In Figure 3A or Figure 4A, the relay optical system 43 includes a double Gauss lens, which comprises a pair of lens groups having optical symmetry in the optical axis direction.

[0064] Here, the operation of the first off-axis aberration correction optical system 40 according to this embodiment will be described.

[0065] Figures 3A and 3B illustrate the first operating state of the first off-axis aberration correction optical system 40 according to the embodiment. Figure 3A shows an explanatory diagram of the operation of the first off-axis aberration correction optical system 40 in a stopped state, where the deflection operation of the first off-axis aberration scanner 401 and the second off-axis aberration scanner 402 remains stopped. Figure 3B schematically shows an example of the convergence position of the measurement light LS incident on the eye under examination E in the stopped state described above, when the focus adjustment of the optical system is completed so that the focal position of the measurement light LS is positioned relative to the center of the fundus Ef (a position corresponding to the optical axis of the optical system). Note that the stopped state described above corresponds to a state in which the first off-axis aberration correction optical system 40 is not positioned in the optical path of the measurement light LS. In Figures 3A and 3B, the same reference numerals are used for parts that are the same as in Figure 1, and explanations are omitted as appropriate.

[0066] The relay optical system 403 includes a double Gauss lens having a first lens group 403a and a second lens group 403b. The first lens group 403a and the second lens group 403b have symmetry in their optical properties in the direction of the optical axis.

[0067] The measurement light LS, which enters the first off-axis aberration correction optical system 40 and passes through the first lens group 403a, forms an image on a plane perpendicular to the optical axis at the fundus conjugate position P between the first lens group 403a and the second lens group 403b. The light from the image formed on this plane is guided to the fundus Ef of the eye under examination via the second lens group 403b. Consequently, the influence of off-axis aberrations in the optical systems preceding and following the relay optical system 403 becomes large, and the convergence position of the light from the image formed on the plane at the fundus conjugate position P shown in Figure 3A shifts from the fundus surface as it moves away from the center of the fundus Ef (Figure 3B).

[0068] Figures 4A and 4B illustrate the second operating state of the first off-axis aberration correction optical system 40 according to the embodiment. Figure 4A is an explanatory diagram of the operation of the first off-axis aberration correction optical system 40 in a deflection operation state in which the deflection operation of the first off-axis aberration scanner 401 and the second off-axis aberration scanner 402 is in progress. Figure 4B, similar to Figure 3B, schematically shows an example of the convergence position of the measurement light LS incident on the eye E under examination in the above deflection operation state when the focus adjustment of the optical system is completed. In Figures 4A and 4B, the same reference numerals are used for parts that are the same as in Figure 1 or Figure 3A, and explanations are omitted as appropriate.

[0069] The measurement light LS, which enters the first off-axis aberration correction optical system 40 and passes through the first lens group 403a, is deflected (scanned) by the first off-axis aberration scanner 401, forming an image at the image plane position at the fundus conjugate position P between the first lens group 403a and the second lens group 403b. At this time, the first off-axis aberration scanner 401 forms an image with off-axis aberrations that cancel out the off-axis aberrations of the optical systems preceding and following the relay optical system 403. These off-axis aberrations can be adjusted by changing the direction of incidence of the measurement light LS to the first lens group 403a using the first off-axis aberration scanner 401. The light from the image formed at this image plane position is descanned by the second off-axis aberration scanner 402 via the second lens group 403b and guided to the second off-axis aberration correction optical system 41.

[0070] The first lens group 403a and the second lens group 403b may have the same power. In this case, the first off-axis aberration scanner 401 and the second off-axis aberration scanner 402 can be controlled to perform deflection operations in the same deflection direction at the same deflection angle.

[0071] Therefore, according to this embodiment, the off-axis aberrations of the optical systems preceding and following the relay optical system 403 are canceled out, and the light from the image formed on the plane at the fundus conjugate position P shown in Figure 4A converges on the fundus surface even in the peripheral part of the fundus Ef (Figure 4B).

[0072] (Second off-axis aberration correction optical system 41) The second off-axis aberration correction optical system 41 deflects the measurement light LS emitted from the first off-axis aberration correction optical system 40 and irradiates it onto the lens, thereby forming an image with off-axis aberrations that cancels out-axis aberrations in the optical system in front of (light source side) or behind (eye side) the lens at the fundus conjugate position P. Furthermore, the second off-axis aberration correction optical system 41 performs a descan operation corresponding to the scanning operation on the measurement light LS, descanning the light from the above image and guiding it as focused light to the focus optical system 50.

[0073] As shown in Figure 5 or Figure 6, the second off-axis aberration correction optical system 41 includes an off-axis aberration scanner 411 and a relay optical system 413. The off-axis aberration scanner 411 has a base, a first deflection surface 411a provided on the first surface of the base, and a second deflection surface 411b provided on the second surface on the back surface of the first surface of the base. In this case, the normal direction of the first deflection surface 411a is substantially the same as the normal direction of the second deflection surface 411b.

[0074] In some embodiments, the substrate has three or more faces, including a first face and a second face. In this case, the normal direction of the first deflection surface 411a may intersect the normal direction of the second deflection surface 411b.

[0075] In some embodiments, a first deflection surface 411a is formed by providing a reflective member on the first surface. Furthermore, a second deflection surface 411b is formed by providing a reflective member on the second surface.

[0076] The first deflection surface 411a and the second deflection surface 411b are positioned at or near positions that are optically conjugate to each other (i.e., optically approximately conjugate positions). Inside the relay optical system 413, the fundus conjugate position P is located.

[0077] In some embodiments, the first deflection surface 411a and the second deflection surface 411b are positioned at the pupillary conjugate position Q.

[0078] Since the first deflection surface 411a and the second deflection surface 411b are provided on a single base, they perform deflection operations in sync with each other. More specifically, the deflection at the first deflection surface 411a and the deflection at the second deflection surface 411b are performed in sync with the deflection operation of the optical scanner 60, which will be described later.

[0079] In this embodiment, the off-axis aberration to be compensated for in the second off-axis aberration correction optical system 41 is astigmatism. In this case, the off-axis aberration scanner 411 is a two-axis scanner.

[0080] Furthermore, if the off-axis aberration to be compensated is a third-order aberration other than field curvature and astigmatism (coma aberration, astigmatism, or distortion aberration), or an aberration of a higher order than third order, the off-axis aberration scanner 411 is a two-axis scanner.

[0081] The relay optical system 413 includes one or more reflective members and one or more lenses. In Figure 5 or Figure 6, the one or more reflective members include plane mirrors 413a, 413b, and 413c. Also in Figure 5 or Figure 6, the one or more lenses include a double Gauss lens comprising a pair of lens groups (first lens group 413d, second lens group 413e) having symmetry in their optical properties along the optical axis. The first lens group 413d is positioned between the off-axis aberration scanner 411 and the plane mirror 413a. The second lens group 413e is positioned between the plane mirror 413c and the off-axis aberration scanner 411.

[0082] Light incident on the second off-axis aberration correction optical system 41 is deflected by the first deflection surface 411a of the off-axis aberration scanner 411 and guided to the first lens group 413d. Light passing through the first lens group 413d is deflected by the plane mirror 413a and guided to the plane mirror 413b. Light deflected by the plane mirror 413b is guided to the plane mirror 413c. Light guided to the plane mirror 413c passes through the second lens group 413e, is deflected by the second deflection surface 411b of the off-axis aberration scanner 411, and guided to the focus optical system 50. In Figure 5 or Figure 6, the fundus conjugate position P is positioned between the plane mirror 413a and the plane mirror 413b.

[0083] Here, the operation of the second off-axis aberration correction optical system 41 according to this embodiment will be described.

[0084] Figure 5 shows an explanatory diagram of the first operating state of the second off-axis aberration correction optical system 41 according to the embodiment. In Figure 5, the same reference numerals are used for parts that are the same as in Figure 1, and explanations are omitted as appropriate. In Figure 5, the configurations of the first lens group 413d and the second lens group 413e are schematically illustrated.

[0085] The measurement light LS, which enters the second off-axis aberration correction optical system 41 and passes through the first lens group 413d, forms an image on a plane perpendicular to the optical axis at the fundus conjugate position P between the first lens group 413d and the second lens group 413e. The light from the image formed on this plane is guided to the fundus Ef of the eye under examination via the second lens group 413e. Consequently, the influence of off-axis aberrations in the optical systems preceding and following the relay optical system 413 becomes large, and the light from the image formed on the plane at the fundus conjugate position P shown in Figure 5, as shown in Figure 3A, shifts its convergence position from the fundus surface as it moves away from the center of the fundus Ef.

[0086] Figure 6B shows an explanatory diagram of the second operating state of the second off-axis aberration correction optical system 41 according to the embodiment. In Figure 6, the same reference numerals are used for parts that are the same as in Figure 1 or Figure 5, and explanations are omitted as appropriate. In Figure 6, for the sake of explanation, the case where the off-axis aberration is field curvature is shown, but the same applies when the off-axis aberration is astigmatism.

[0087] The measurement light LS incident on the second off-axis aberration correction optical system 41 is deflected (scanned) by the first deflection surface 411a of the off-axis aberration scanner 411, forming an image at the image plane position at the fundus conjugate position P between the first lens group 413d and the second lens group 413e. At this time, the off-axis aberration scanner 411 forms an image with off-axis aberrations that cancel out the off-axis aberrations of the optical systems preceding and following the relay optical system 43. These off-axis aberrations can be adjusted by changing the direction of incidence of the measurement light LS to the first lens group 413d using the first deflection surface 411a of the off-axis aberration scanner 411. The light from the image formed at this image plane position passes through the second lens group 413e, is descanned by the second deflection surface 411b of the off-axis aberration scanner 411, and is guided to the fundus Ef of the eye under examination E.

[0088] The first lens group 413d and the second lens group 413e may have the same power. In this case, the optical magnification will be the same on the incident and exit sides of the second off-axis aberration correction optical system 41, simplifying the optical design.

[0089] Therefore, according to this embodiment, the off-axis aberrations of the preceding and succeeding optical systems of the relay optical system 413 are canceled out, and the light from the image formed on the plane at the fundus conjugate position P shown in Figure 6 converges on the fundus surface even in the peripheral part of the fundus Ef, as in the case shown in Figure 4B.

[0090] (Focus optical system 50) The focusing optical system 50 is positioned between the second off-axis aberration correction optical system 41 and the optical scanner 60, and changes the focal position of the measurement light LS that passes through the first off-axis aberration correction optical system 40 and the second off-axis aberration correction optical system 41. The focusing optical system 50 includes two or more lenses, and the focal position of the measurement light LS can be changed by relatively changing the positions of the two or more lenses in the direction of the optical axis.

[0091] (Optical scanner 60) The optical scanner 60 is either a single-axis or a double-axis scanner. The optical scanner 60 (deflection surface) can be positioned at the pupil conjugate position Q. For example, in this embodiment, the optical scanner 60 is a double-axis scanner. The optical scanner 60 includes a galvanometer scanner, a MEMS (Micro Electro Mechanical System) scanner, a polygon mirror, or a resonant scanner.

[0092] If the ophthalmic device 1 according to the embodiment has the function of a scanning laser ophthalmoscope, the optical scanner 60 is a biaxial scanner. If the ophthalmic device 1 according to the embodiment has the function of a slit-scan type ophthalmic imaging device, the optical scanner 60 is a uniaxial scanner configured to deflect the slit light in a direction perpendicular to the longitudinal direction of the slit light.

[0093] The optical scanner 60 changes the angle of the deflection plane (deflection angle) under control from the control unit described later. This allows the deflection direction (scanning direction) of the measurement light LS to be controlled while changing the irradiation position of the measurement light LS in the fundus Ef.

[0094] (Objective optical system 70) The objective optical system 70 is a refractive optical system having one or more lenses, including an objective lens. The measurement light LS, deflected by the optical scanner 60, enters the eye through the pupil Ep of the eye under examination E via the objective optical system 70.

[0095] Note that the configuration of the ophthalmic device 1 shown in Figure 1 is merely an example. For example, the interference optical system 10, collimator lens 20, optical path length correction unit 30, focusing optical system 50, and objective optical system 70 have no technical relationship with the first off-axis aberration correction optical system 40 and the second off-axis aberration correction optical system 41 from the viewpoint of off-axis aberration correction. Therefore, the ophthalmic device 1 may have a configuration in which at least one of the collimator lens 20, optical path length correction unit 30, focusing optical system 50, and objective optical system 70 is omitted from the configuration shown in Figure 1.

[0096] <Control System> Figure 7 shows an example of the configuration of the control system of the ophthalmic device 1 according to the embodiment. Figure 7 is a block diagram of an example of the configuration of the control system of the ophthalmic device 1 according to the embodiment. In Figure 7, the same reference numerals are used for parts that are the same as in Figure 1, and explanations are omitted as appropriate.

[0097] The control system (processing system) of the ophthalmic device 1 is centered around the control unit 200. The control unit 200 controls each part of the ophthalmic device 1.

[0098] The control unit 200 includes a main control unit 210 and a storage unit 220. The functions of the main control unit 210 are realized, for example, by one or more processors. The storage unit 220 has a computer program for controlling the ophthalmic device 1 pre-stored in it. This computer program includes a program for controlling the wavelength-swept light source, a program for controlling the detector, a program for controlling the DAQ, a program for correcting the optical path length, a program for correcting the first off-axis aberration, a program for correcting the second off-axis aberration, a program for controlling the focus, a program for controlling the optical scanner, an image forming program, a data processing program, and a user interface program. The control unit 200 executes control processing by operating the main control unit 210 according to such a computer program.

[0099] (Main control unit 210) The main control unit 210 controls the interference optical system 10, the optical path length correction unit 30, the first off-axis aberration correction optical system 40, the second off-axis aberration correction optical system 41, the focus optical system 50, the optical scanner 60, the DAQ 80, the image forming unit 90, the data processing unit 100, the operation unit 110, and the display unit 120.

[0100] Control of the interference optical system 10 includes control of the wavelength-swept light source 11 and control of the detector 14.

[0101] Control of the wavelength-swept light source 11 includes controlling wavelength sweep parameters, which include at least one of the following: the start wavelength of the sweep, the end wavelength of the sweep, the wavelength sweep range, the wavelength sweep speed, or the wavelength sweep timing. For example, the main control unit 210 can control the wavelength-swept light source 11 by setting the wavelength sweep parameters.

[0102] Control of the detector 14 includes control of exposure time (charge accumulation time), sensitivity, and frame rate.

[0103] Control of the optical path length correction unit 30 includes controlling the movement of the retroreflector along the optical path of the measurement light LS. For example, the optical path length correction unit 30 includes a retroreflector and an actuator that drives the retroreflector. The main control unit 210 moves the retroreflector along the optical path of the measurement light LS by controlling the actuator. This makes it possible to change the relative optical paths of the reference light LR and the measurement light LS, thereby changing the depth position of the fundus of the target of imaging.

[0104] Control of the first off-axis aberration correction optical system 40 includes control of the first off-axis aberration scanner 401 and control of the second off-axis aberration scanner 402. The main control unit 210 performs deflection control of the first off-axis aberration scanner 401 and deflection control of the second off-axis aberration scanner 402 in synchronization with the deflection control of the optical scanner 60, which will be described later.

[0105] For example, the main control unit 210 controls the first off-axis aberration scanner 401 and the second off-axis aberration scanner 402 based on first deflection control information set in advance according to the eye E under examination. In this embodiment, by setting the first lens group 403a and the second lens group 403b to the same power, the first off-axis aberration scanner 401 and the second off-axis aberration scanner 402 can be controlled in the same deflection direction and at the same deflection angle.

[0106] The first deflection control information is information in which the deflection angles of the deflection planes of the first off-axis aberration scanner 401 and the second off-axis aberration scanner 402 are pre-associated with the irradiation position (scan position) of the measurement light LS deflected by the optical scanner 60 at the fundus Ef. The irradiation position of the measurement light LS at the fundus Ef can be determined by the deflection angle of the deflection plane of the optical scanner 60. Therefore, the first deflection control information may be information in which the deflection angles of the deflection planes of the first off-axis aberration scanner 401 and the second off-axis aberration scanner 402 are pre-associated with the deflection angle (scanning angle) of the deflection plane of the optical scanner 60.

[0107] Control of the second off-axis aberration correction optical system 41 includes control of the off-axis aberration scanner 411. The main control unit 210 performs deflection control of the off-axis aberration scanner 411 in synchronization with the deflection control of the optical scanner 60, which will be described later.

[0108] For example, the main control unit 210 controls the off-axis aberration scanner 411 based on a second deflection control information set in advance according to the eye E under examination. In this embodiment, the off-axis aberration scanner 411 performs scanning with a first deflection surface 411a provided on a single base and descans with a second deflection surface 411b, so that scanning and descanning can be synchronized with high precision with a simple configuration.

[0109] The second deflection control information, like the first deflection control information, is information in which the deflection angles of the deflection surfaces (first deflection surface 411a, second deflection surface 411b) of the off-axis aberration scanner 411 are pre-associated with the irradiation position (scan position) of the measurement light LS deflected by the optical scanner 60 at the fundus Ef. The second deflection control information may be information in which the deflection angle of the deflection surface of the off-axis aberration scanner 411 is pre-associated with the deflection angle (scan angle) of the deflection surface of the optical scanner 60.

[0110] Control of the focus optical system 50 includes controlling the relative positions of two or more lenses along the optical axis. This makes it possible to take images that are in focus on the central area, including the position corresponding to the optical axis in the fundus Ef.

[0111] Control of the optical scanner 60 includes controlling the angle of the deflection plane. Controlling the angle of the deflection plane of the optical scanner 60 involves controlling deflection control parameters, which include at least one of the deflection start angle, deflection end angle, deflection angle range, or deflection speed. For example, the main control unit 210 can control the scan range (scan start position and scan end position) and scan speed by controlling the deflection control parameters.

[0112] The main control unit 210 controls the optical scanner 60 to deflect the measurement light LS according to a deflection pattern corresponding to a pre-set scan mode. Examples of such scan modes include raster scan (line scan), cross scan, circle scan, radial scan, concentric circle scan, multi-line cross scan, and spiral scan. Furthermore, scan modes may also include Lissajous scan and 3D scan (including scans combining slow and fast scans).

[0113] The DAQ80 includes an A / D converter. The A / D converter samples the interferogram signal, which is the input analog signal, at a predetermined sampling frequency. The DAQ80 samples the detection signal from the detector 14 at a sampling timing synchronized with the k-clock signal from the wavelength-swept light source 11. The signal after A / D conversion is stored in the storage unit 220 under the control of the main control unit 210.

[0114] The image forming unit 90 forms image data of a tomographic image (broadly speaking, an OCT image) of the fundus Ef based on the detection signal (interference signal) obtained after sampling by the DAQ 80. That is, the image forming unit 90 forms an OCT image of the eye under examination E based on the detection result of the interference light LC by the interference optical system 10. This process includes processing such as noise reduction, filtering, and FFT (Fast Fourier Transform), similar to conventional swept-source type optical coherence tomography. The image data acquired in this way is a dataset containing a group of image data formed by imaging the reflectance intensity profiles of multiple A-lines (paths of each measurement light LS within the eye under examination E). The image forming unit 90 can form an OCT image by imaging the reflectance intensity profiles and arranging them in a one-dimensional, two-dimensional, or three-dimensional direction. Examples of OCT images include A-scan images, B-scan images, and C-scan images.

[0115] To improve image quality, multiple datasets collected by repeatedly scanning the same pattern can be superimposed (averaged).

[0116] The data processing unit 100 performs various data processing (image processing) and analysis processes on the detection results of the interference light LC or the image formed by the image forming unit 90. For example, the data processing unit 100 performs various correction processes such as analysis of the signal-to-noise ratio of the interference signal, brightness correction of the image, and dispersion correction.

[0117] Furthermore, the data processing unit 100 performs known image processing, such as interpolation to interpolate pixels between tomographic images, to form image data of a three-dimensional image of the fundus Ef. Three-dimensional image data refers to image data in which the position of pixels is defined by a three-dimensional coordinate system. Three-dimensional image data can consist of voxels arranged in three dimensions. This image data is called volume data or voxel data. When displaying an image based on volume data, the data processing unit 100 performs rendering processing (such as volume rendering or MIP (Maximum Intensity Projection)) on this volume data to form pseudo-three-dimensional image data as viewed from a specific line of sight. This pseudo-three-dimensional image is displayed on a display device such as the display unit 120.

[0118] Furthermore, it is possible to form stacked data of multiple tomographic images as 3D image data. Stacked data is image data obtained by arranging multiple tomographic images obtained along multiple scan lines in a 3D manner based on the positional relationship of the scan lines. In other words, stacked data is image data obtained by representing multiple tomographic images, which were originally defined by separate 2D coordinate systems, using a single 3D coordinate system (i.e., embedding them in a single 3D space).

[0119] Furthermore, the data processing unit 100 can generate en-face images or projection images from 3D images, or generate OCTA (OCT Angiography) images from multiple time-series tomographic images using known methods.

[0120] The operation unit 110 includes an operation device for receiving user input. The operation unit 110 may also include various buttons and keys provided on the housing or externally of the ophthalmic device 1. The main control unit 210 controls each part of the ophthalmic device 1 based on operation instruction signals corresponding to the user input from the operation unit 110.

[0121] The display unit 120 includes a display device. The display unit 120 receives control from the main control unit 210 and displays various information.

[0122] Furthermore, the operation unit 110 and the display unit 120 do not necessarily need to be configured as separate devices. For example, it is possible to use a device that integrates display and operation functions, such as a touch panel. In that case, the operation unit 110 would consist of this touch panel and a computer program. The operations performed on the operation unit 110 are input to the control unit 200 as electrical signals. Alternatively, operations and information input may be performed using a graphical user interface (GUI) displayed on the display unit 120 and the operation unit 110.

[0123] (Storage unit 220) The memory unit 220 stores various types of data (signals). The data stored in the memory unit 220 includes first deflection control information, second deflection control information, detection signals after A / D conversion acquired by the DAQ 80, image data of the image formed by the image forming unit 90, data processing results by the data processing unit 100, and subject eye information. The first deflection control information is for synchronously controlling the first off-axis aberration scanner 401 and the second off-axis aberration scanner 402, or for controlling the first off-axis aberration scanner 401 and the second off-axis aberration scanner 402 in synchronization with the deflection operation of the optical scanner 60. The second deflection control information is for controlling the off-axis aberration scanner 411 in synchronization with the deflection operation of the optical scanner 60. Subject eye information includes information about the subject, such as patient ID and name, and information about the subject eye, such as left eye / right eye identification information.

[0124] Furthermore, the memory unit 220 stores various programs and data necessary for operating the ophthalmic device 1.

[0125] [Control example] Next, we will describe control examples for the first off-axis aberration scanner 401 and the second off-axis aberration scanner 402 in the first off-axis aberration correction optical system 40, and the off-axis aberration scanner 411 in the second off-axis aberration correction optical system 41.

[0126] (First control example) The first control example is a control example where the measurement light LS is deflected by raster scanning using an optical scanner 60.

[0127] Figure 8 shows an explanatory diagram of the process of performing a fundus scan using a raster scan with a measurement light LS on the fundus Ef. Figure 8 schematically represents the trajectory of the raster scan on a frontal image of the fundus Ef. In Figure 8, the horizontal direction perpendicular to the optical axis of the optical system is the X direction (high-speed axis direction), and the vertical direction perpendicular to the optical axis is the Y direction (low-speed axis direction).

[0128] In the first control example, the raster scan is performed in the order of line scans SC1, SC2, ..., SC9. A three-dimensional image of the fundus Ef can be obtained using the nine tomographic images obtained from line scans SC1 to SC9.

[0129] Figure 9 schematically shows an example of the control timing for the optical scanner 60 and the control timing for the first off-axis aberration scanner 401, the second off-axis aberration scanner 402, and the off-axis aberration scanner 411 (X direction, Y direction) when performing the raster scan shown in Figure 8. In this embodiment, the deflection control for the first off-axis aberration scanner 401 is the same as the deflection control for the second off-axis aberration scanner 402. Therefore, Figure 9 illustrates the control timing for a single "off-axis aberration scanner" common to both the first off-axis aberration scanner 401 and the second off-axis aberration scanner 402. In Figure 9, the horizontal axis is the time axis, and the vertical axis represents the deflection angle (scanning angle) of the scanner (deflection plane).

[0130] The Y-direction deflection of the optical scanner 60 enables the function of a fundus scanning Y-direction scanner. The X-direction deflection of the optical scanner 60 enables the function of a fundus scanning X-direction scanner. As shown in Figure 9, the raster scan sequentially performs line scans SC1 to SC9 in the X direction while changing the scan position in the Y direction. At this time, the first off-axis aberration scanner 401 and the second off-axis aberration scanner 402 are each deflected during each line scan so that the deflection angle of the polarization plane is minimized at the center of the fundus Ef and increases towards the periphery of the fundus Ef. In addition, in the example shown in Figure 9, the off-axis aberration scanner 411 is deflected during each line scan so that the X and Y direction deflection angles of the polarization plane are minimized at the center of the fundus Ef and increase towards the periphery of the fundus Ef.

[0131] Figure 10 schematically shows the optical path diagram of the optical system of Figure 1 in the stopped state shown in Figures 3A, 3B, and 5. In Figure 10, in the first off-axis aberration correction optical system 40, the position of the first off-axis aberration scanner 401 (deflection surface) and the position of the second off-axis aberration scanner 402 (deflection surface), which is positioned optically approximately conjugate to the position of the first off-axis aberration scanner 401 (deflection surface), are shown as "R1". Also, in the second off-axis aberration correction optical system 41, the position of the first deflection surface 411a and the position of the second deflection surface 411b, which is positioned optically approximately conjugate to the position of the first deflection surface 411a, are shown as "R2". In Figure 10, the same reference numerals are used for parts that are the same as in Figures 1, 3A, or 5, and explanations are omitted as appropriate.

[0132] As shown in Figure 10, in the stationary state shown in Figures 3A, 3B, and 5, the measurement light LS converges at a position in the depth direction relative to the fundus surface in the peripheral part of the fundus Ef where the deflection angle by the optical scanner 60 is large.

[0133] Figure 11 schematically shows the optical path diagram of the optical system of Figure 1 in the deflection operation states shown in Figures 4A, 4B, and 6. In Figure 11, the same reference numerals are used for parts that are the same as those in Figures 1, 4A, 6, or 10, and explanations are omitted as appropriate.

[0134] As shown in Figure 11, in the deflection operation states shown in Figures 4A, 4B, and 6, the first off-axis aberration scanner 401 deflects the measurement light LS to form an image (image plane) with off-axis aberrations that cancel out the curved image plane at the fundus conjugate position P in the relay optical system 403. The second off-axis aberration scanner 402 descans the light from the formed image. In addition, the first deflection surface 411a of the off-axis aberration scanner 411 deflects the measurement light LS emitted by the first off-axis aberration correction optical system 40 in the X and Y directions to form an image (image plane) with off-axis aberrations that cancel out astigmatism at the fundus conjugate position P in the relay optical system 413. The second deflection surface 411b of the off-axis aberration scanner 411 descans the light from the formed image.

[0135] The optical scanner 60 deflects the measurement light LS, which is descanned by the second off-axis aberration correction optical system 41. As a result, the curved image plane and astigmatism of the measurement light LS incident on the fundus Ef are canceled out. This ensures that the measurement light LS converges at the fundus surface even in the peripheral areas of the fundus Ef where the deflection angle by the optical scanner 60 is large.

[0136] (Second control example) The second control example is a control example in which the measurement light LS is deflected by radial scanning using the optical scanner 60.

[0137] Figure 12 shows an explanatory diagram of the procedure for performing a fundus scan using a radial scan with a measurement light LS on the fundus Ef. Figure 12 schematically represents the trajectory of the radial scan on a frontal image of the fundus Ef. In Figure 12, the horizontal direction perpendicular to the optical axis of the optical system is the X direction, and the vertical direction perpendicular to the optical axis is the Y direction.

[0138] In the second control example, radial scans are performed in the order of line scans SC11, SC12, ..., SC19. A three-dimensional image of the fundus Ef can be obtained using the nine tomographic images obtained from line scans SC11 to SC19.

[0139] Figure 13 schematically shows an example of the control timing for the optical scanner 60 and the control timing for the first off-axis aberration scanner 401, the second off-axis aberration scanner 402, and the off-axis aberration scanner 411 when performing the radial scan shown in Figure 12. Note that, similar to Figure 9, Figure 13 illustrates the control timing for a single "off-axis aberration scanner" common to both the first off-axis aberration scanner 401 and the second off-axis aberration scanner 402. In Figure 13, the horizontal axis represents the time axis, and the vertical axis represents the deflection angle (scanning angle) of the scanner (deflection plane).

[0140] As shown in Figure 13, radial scanning is performed by sequentially executing line scans SC11 to SC19 such that the scan position changes in the X and Y directions during each line scan. At this time, the first off-axis aberration scanner 401 and the second off-axis aberration scanner 402 are each deflected so that the deflection angle of the polarization plane decreases monotonically (or increases monotonically) during each line scan. Therefore, it is not necessary to change the deflection direction during line scanning, and it becomes possible to control the deflection of the first off-axis aberration scanner 401 and the second off-axis aberration scanner 402 with higher precision compared to the first control example.

[0141] Furthermore, in the example shown in Figure 13, the off-axis aberration scanner 411 is deflected so that the deflection angles in the X and Y directions of the polarization plane monotonically decrease (or monotonically increase) during each line scan. Therefore, it is not necessary to change the deflection direction during a line scan, and it becomes possible to control the deflection of the off-axis aberration scanner 411 with higher precision compared to the first control example.

[0142] Ophthalmic device 1 is an example of a "light scanning device" according to the embodiment. Eye E under examination is an example of a "measured object" according to the embodiment. Fundus Ef is an example of a "measurement site" according to the embodiment. Off-axis aberration is an example of an "aberration" according to the embodiment. Field curvature is an example of a "first aberration" according to the embodiment. The image formed by the first off-axis aberration scanner 401 is an example of a "first image" according to the embodiment. Astigmatism (or coma aberration) is an example of a "second aberration" according to the embodiment. The image formed by the off-axis aberration scanner 411 is an example of a "second image" according to the embodiment. A reflective member provided on the first deflection surface 411a of the first off-axis aberration scanner 401 or off-axis aberration scanner 411 is an example of a "first deflection member" according to the embodiment. A reflective member provided on the second deflection surface 411b of the second off-axis aberration scanner 402 or off-axis aberration scanner 411 is an example of a "second deflection member" according to the embodiment. The optical scanner 60 is an example of a "scanning optical system" or "two-axis scanner" according to the embodiment. The first deflection surface 411a is an example of a "first surface" according to the embodiment. The second deflection surface 411b is an example of a "second surface" according to the embodiment.

[0143] <Example of operation> Next, an example of the operation of the ophthalmic device 1 according to the embodiment will be described. The following example of operation describes the case in which off-axis aberrations, namely field curvature and astigmatism, are corrected according to the eye being examined. However, the following embodiment can be applied when correcting a combination of two off-axis aberrations other than the combination of field curvature and astigmatism, according to the eye being examined.

[0144] Figure 14 shows an example of operation of the ophthalmic device 1 according to the embodiment. Figure 14 is a flowchart of the operation example of the ophthalmic device 1 according to the embodiment. The memory unit 220 stores a computer program for realizing the process shown in Figure 14. The main control unit 210 executes the process shown in Figure 14 by operating according to this computer program.

[0145] (S1: Corrects optical path length) First, the main control unit 210 controls the optical path length correction unit 30 to relatively change the optical path length of the reference light LR and the optical path length of the measurement light LS.

[0146] In some embodiments, the main control unit 210 repeatedly performs OCT scans, causing the image forming unit 90 to form tomographic images, and displays the formed tomographic images in real time on the display unit 120. The user refers to the tomographic images displayed on the display unit 120 and operates the operation unit 110 so that a desired portion of the tomographic image is positioned at a desired depth. The main control unit 210 controls the optical path length correction unit 30 based on operation information corresponding to the user's operations from the operation unit 110.

[0147] In some embodiments, the main control unit 210 repeatedly performs OCT scans, causing the image forming unit 90 to form tomographic images, and causes the data processing unit 100 to identify desired layer regions in the formed tomographic images. The main control unit 210 controls the optical path length correction unit 30 so that the identified desired layer regions are positioned at desired depth positions in the tomographic images.

[0148] (S2: Set scan area) Next, the main control unit 210 sets a scan area corresponding to the range in which the OCT scan is performed on the fundus Ef.

[0149] In some embodiments, the main control unit 210 repeatedly performs 3D OCT scans, causing the image forming unit 90 to form OCT images, and then causes the data processing unit 100 to form a frontal image (en-face image, etc.) of the fundus Ef in real time from the formed OCT images. The user sets the desired scan area using the operation unit 110 on the real-time frontal image displayed on the display unit 120. Based on the user's operation on the operation unit 110, the main control unit 210 identifies the scan area on the fundus Ef and sets the identified scan area.

[0150] In some embodiments, the data processing unit 100 analyzes the frontal image of the fundus Ef acquired in real time and identifies a predetermined area. The main control unit 210 sets the area including the predetermined area identified by the data processing unit 100 as the scan area.

[0151] In some embodiments, the process of step S1 is executed after the process of step S2.

[0152] (S3: Focus adjustment for the center) Next, the main control unit 210 controls the focus optical system 50 to adjust the focus so that the convergence position of the measurement light LS is located in the center of the fundus Ef, which includes a position corresponding to the optical axis of the objective optical system 70.

[0153] In some embodiments, the user operates the operation unit 110 while referring to the real-time frontal image displayed on the display unit 120. The main control unit 210 changes the convergence position of the measurement light LS by controlling the focus optical system 50 based on the user's operations on the operation unit 110. The generation of the real-time frontal image and focus adjustment are repeated until the user determines that focus adjustment is complete by looking at the frontal image of the fundus Ef.

[0154] In some embodiments, the data processing unit 100 analyzes the frontal image of the fundus Ef acquired in real time and calculates an evaluation value for the image quality of the frontal image. When the main control unit 210 determines that the calculated image quality evaluation value is less than a predetermined threshold, it controls the focus optical system 50 to change the convergence position of the measurement light LS. The main control unit 210 repeats the generation of the real-time frontal image and focus adjustment described above until the image quality evaluation value is determined to be equal to or greater than the predetermined threshold.

[0155] (S4: Adjust off-axis aberration scanner) Next, the main control unit 210 adjusts the first off-axis aberration scanner 401, the second off-axis aberration scanner 402, and the off-axis aberration scanner 411. This adjustment includes determining the deflection angles of the first off-axis aberration scanner 401, the second off-axis aberration scanner 402, and the off-axis aberration scanner 411 corresponding to the scan position of the optical scanner 60 in order to generate off-axis aberrations corresponding to the eye E under examination. For example, the main control unit 210 adjusts the first deflection control information for controlling the first off-axis aberration scanner 401 and the second off-axis aberration scanner 402, and the second deflection control information for controlling the off-axis aberration scanner 411, according to the eye E under examination.

[0156] Details of the process in step S4 will be described later.

[0157] (S5: OCT scan) Next, the main control unit 210 performs an OCT scan on the scan area of ​​the fundus Ef set in step S2.

[0158] Specifically, the main control unit 210 controls the wavelength-swept light source 11 to start the wavelength sweep operation of the light source light. The main control unit 210 starts deflection control of the optical scanner 60 based on the scan area set in step S2, and also starts deflection control of the first off-axis aberration scanner 401 and the second off-axis aberration scanner 402 based on the first deflection control information. Furthermore, the main control unit 210 starts deflection control of the off-axis aberration scanner 411 based on the second deflection control information. The main control unit 210 controls the detector 14 and DAQ 80 to sequentially acquire interferogram signals corresponding to the detection results of interference light and store them in the storage unit 220.

[0159] (S6: Forms an OCT image) Next, the main control unit 210 controls the image forming unit 90 to form an OCT image based on the interferogram signal acquired in step S5.

[0160] This concludes the operation of ophthalmic device 1 (end).

[0161] Note that the process shown in Figure 14 is only one example of the operation of the ophthalmic device 1. Steps S1, S2, S3, S5, and S6 have no technical relationship with step S4 in terms of off-axis aberration correction. Therefore, the ophthalmic device 1 may be configured to perform a process in which at least one of steps S1, S2, S3, S5, and S6 is omitted from the process shown in Figure 14.

[0162] The process in step S4 shown in Figure 14 is performed according to the processes shown in Figures 15A and 15B. Specifically, the processes shown in Figures 15A and 15B are performed for each off-axis aberration correction optical system. In this case, with the deflection operation of the off-axis aberration scanner 411 in the second off-axis aberration correction optical system 41 stopped, first deflection control information is generated to control the first off-axis aberration scanner 401 and the second off-axis aberration scanner 402 in the first off-axis aberration correction optical system 40. Subsequently, with the deflection operation of the first off-axis aberration scanner 401 and the second off-axis aberration scanner 402 in the first off-axis aberration correction optical system 40 stopped, second deflection control information is generated to control the off-axis aberration scanner 411 in the second off-axis aberration correction optical system 41.

[0163] Since the first deflection control information and the second deflection control information can be generated in the same way, the following will describe the case in which the first deflection control information is generated while the deflection operation of the off-axis aberration scanner 411 is stopped.

[0164] Figures 15A and 15B show an example of the process in step S4 of Figure 14. Figures 15A and 15B represent flowcharts of the process in step S4 of Figure 14. The memory unit 220 stores a computer program for implementing the processes shown in Figures 15A and 15B. The main control unit 210 operates according to this computer program and executes the processes shown in Figures 15A and 15B.

[0165] In step S4, the deflection angle at which the interference intensity of the peripheral portion of the fundus Ef depicted in the tomographic image obtained by repeatedly performing OCT scans while changing the deflection angles of the first off-axis aberration scanner 401 and the second off-axis aberration scanner 402 is maximized is identified. When the interference intensity of the peripheral portion of the fundus Ef is maximized, it is determined that the field curvature has been well corrected.

[0166] (S11: Set the initial value of the deflection angle of the off-axis aberration scanner (when scanning in the X direction)) First, the main control unit 210 sets the deflection angle of the first off-axis aberration scanner 401 and the second off-axis aberration scanner 402 during X-direction scanning by the optical scanner 60 to an initial value (the deflection angle in the Y direction is 0 degrees).

[0167] (S12: Start of repeated scanning in the X direction) Next, the main control unit 210 controls the interference optical system 10 and the optical scanner 60 to start repeated line scanning in the X direction.

[0168] (S13: Forms an OCT image) Next, the main control unit 210 controls the image forming unit 90 to form a tomographic image as an OCT image based on the interferogram signal acquired in step S12.

[0169] (S14: Obtain interference intensity in the peripheral area) Next, the main control unit 210 controls the data processing unit 100 to identify the peripheral portion of the fundus Ef from the OCT image formed in step S13 and to acquire the interference intensity of the identified peripheral portion.

[0170] Figure 16A shows an explanatory diagram of the operation of step S14. Figure 16A schematically represents a tomographic image obtained by performing a line scan (B-scan) on the scan line SCX in the X direction relative to the fundus Ef.

[0171] The data processing unit 100 obtains the interference intensity of the peripheral part of the fundus Ef from the tomographic image shown in Figure 16A.

[0172] In some embodiments, the data processing unit 100 identifies a predetermined layer region of the fundus Ef and determines the interference intensity based on the brightness information of the layer region (or a representative position of the layer region) in the peripheral part of the fundus Ef. The representative position may be the center position of the layer region, the centroid position, the position with maximum or minimum brightness, or the position furthest or closest to the center of the fundus Ef within the layer region. The interference intensity may be a statistical value (maximum value, minimum value, median, or mean value) obtained by statistical processing of the brightness information of two or more layer regions (or representative positions).

[0173] In some embodiments, the peripheral region is the region outside the central region, which includes the center of the fundus Ef. In this case, the central region is the region within a predetermined distance from the center of the fundus Ef, or the region that includes the part corresponding to the center of the fundus Ef. In some embodiments, the peripheral region is the region separated by a predetermined distance from the center of the fundus Ef.

[0174] (S15: Determine the deflection angle?) Following step S14, the main control unit 210 determines, based on the interference intensity of the peripheral area acquired in step S14, whether or not it has completed the identification of the deflection angles of the first off-axis aberration scanner 401 and the second off-axis aberration scanner 402 that can adequately correct the image field curvature.

[0175] For example, the main control unit 210 determines whether the acquisition of interference intensity in step S14 has been completed within a predetermined deflection angle range of the first off-axis aberration scanner 401 and the second off-axis aberration scanner 402. If it is determined that the acquisition of interference intensity in step S14 has been completed within the predetermined deflection angle range (S15:Y), the process in step S4 of Figure 14 proceeds to step S17. If it is determined that the acquisition of interference intensity in step S14 has not been completed within the predetermined deflection angle range (S15:N), the process in step S4 of Figure 14 proceeds to step S16.

[0176] (S16: Change the deflection angle by a predetermined step) In step S15, if it is determined that the acquisition of interference intensity in step S14 has not been completed within a predetermined deflection angle range (S15:N), the main control unit 210 changes the deflection angles of the first off-axis aberration scanner 401 and the second off-axis aberration scanner 402 by a predetermined step.

[0177] After the processing in step S16, the processing in step S4 in Figure 14 proceeds to step S13.

[0178] (S17: Next scanline?) In step S15, when it is determined that the acquisition of interference intensity in step S14 has been completed within a predetermined deflection angle range (S15:Y), the main control unit 210 determines whether or not to similarly determine the deflection angle for the next scan line. Here, the next scan line is an adjacent scan line that is separated from the current scan line by one or more lines in the Y direction.

[0179] In some embodiments, the main control unit 210 determines whether or not to continue determining the deflection angle for the next scan line by determining whether or not the deflection angles of the first off-axis aberration scanner 401 and the second off-axis aberration scanner 402 have been determined for a predetermined number of scan lines.

[0180] If it is determined that the deflection angles of the first off-axis aberration scanner 401 and the second off-axis aberration scanner 402 should be determined for the next scan line (S17:Y), the process in step S4 of Figure 14 proceeds to step S11. If it is determined that the deflection angles of the first off-axis aberration scanner 401 and the second off-axis aberration scanner 402 should not be determined for the next scan line (S17:N), the process in step S4 of Figure 14 proceeds to step S18.

[0181] (S18: Set the initial value of the deflection angle of the off-axis aberration scanner (when scanning in the Y direction)) In step S17, when it is determined that the deflection angle of the off-axis aberration scanner should be determined for the next scan line (S17:Y), the main control unit 210 sets the deflection angle of the first off-axis aberration scanner 401 and the second off-axis aberration scanner 402 during Y-direction scanning by the optical scanner 60 to an initial value (the deflection angle in the X direction is 0 degrees).

[0182] (S19: Start repeated scanning in the Y direction) Next, the main control unit 210 controls the interference optical system 10 and the optical scanner 60 to start repeated line scanning in the Y direction.

[0183] (S20: Forms an OCT image) Next, the main control unit 210 controls the image forming unit 90 to form a tomographic image as an OCT image based on the interferogram signal acquired in step S19.

[0184] (S21: Obtain interference intensity in the peripheral area) Next, the main control unit 210 controls the data processing unit 100 to identify the peripheral portion of the fundus Ef from the OCT image formed in step S20 and to acquire the interference intensity of the identified peripheral portion.

[0185] Figure 16B shows an explanatory diagram of the operation of step S21. Figure 16B schematically represents a tomographic image obtained by performing a line scan (B-scan) on the scan line SCY in the Y direction relative to the fundus Ef.

[0186] The data processing unit 100 obtains the interference intensity of the peripheral portion of the fundus Ef from the tomographic image shown in Figure 16B. The data processing unit 100 can obtain the interference intensity of the peripheral portion of the fundus Ef in the same manner as in step S14.

[0187] (S22: Determine the deflection angle?) Following step S21, the main control unit 210 determines, based on the interference intensity of the peripheral area acquired in step S21, whether or not it has completed the determination of the deflection angles of the first off-axis aberration scanner 401 and the second off-axis aberration scanner 402 that can adequately correct the image field curvature.

[0188] For example, the main control unit 210 can determine, similar to step S15, whether or not it has completed the determination of the deflection angles of the first off-axis aberration scanner 401 and the second off-axis aberration scanner 402 that can effectively correct image field curvature. When it is determined that the acquisition of interference intensity in step S21 has been completed within a predetermined deflection angle range (S22:Y), the process in step S4 of Figure 14 proceeds to step S24. When it is determined that the acquisition of interference intensity in step S21 has not been completed within a predetermined deflection angle range (S22:N), the process in step S4 of Figure 14 proceeds to step S23.

[0189] (S23: Change the deflection angle by a predetermined step) In step S22, if it is determined that the acquisition of interference intensity in step S21 has not been completed within a predetermined deflection angle range (S22:N), the main control unit 210 changes the deflection angles of the first off-axis aberration scanner 401 and the second off-axis aberration scanner 402 by a predetermined step.

[0190] After the processing in step S23, the processing in step S4 in Figure 14 proceeds to step S20.

[0191] (S24: Next scanline?) When it is determined that the acquisition of interference intensity in step S21 has been completed within a predetermined deflection angle range (S22:Y), the main control unit 210 determines whether or not to specify the deflection angles of the first off-axis aberration scanner 401 and the second off-axis aberration scanner 402 for the next scan line. For example, the main control unit 210 can determine whether or not to continue specifying the deflection angle for the next scan line, similar to step S17.

[0192] If it is determined that the deflection angles of the first off-axis aberration scanner 401 and the second off-axis aberration scanner 402 should be determined for the next scan line (S24:Y), the process in step S4 of Figure 14 proceeds to step S18. If it is determined that the deflection angles of the first off-axis aberration scanner 401 and the second off-axis aberration scanner 402 should not be determined for the next scan line (S24:N), the process in step S4 of Figure 14 proceeds to step S25.

[0193] (S25: Interpolation) In step S24, when it is determined that the deflection angle of the off-axis aberration scanner should be determined for the next scan line (S24:Y), the main control unit 210 performs interpolation using the deflection angles of the first off-axis aberration scanner 401 and the second off-axis aberration scanner 402 obtained by repeatedly executing steps S11 to S24. This interpolation process determines the deflection angles of the first off-axis aberration scanner 401 and the second off-axis aberration scanner 402 that can adequately correct image field curvature at positions on the fundus Ef other than the scan position on the scan line that were not performed in steps S11 to S24. In the interpolation process, the deflection angles of the first off-axis aberration scanner 401 and the second off-axis aberration scanner 402 are interpolated in the X and Y directions.

[0194] The main control unit 210 generates deflection control information using the deflection angles of the first off-axis aberration scanner 401 and the second off-axis aberration scanner 402 obtained by repeatedly executing steps S11 to S24, and the deflection angles of the first off-axis aberration scanner 401 and the second off-axis aberration scanner 402 obtained by the interpolation process in step S25.

[0195] This completes the process in step S4 of Figure 14 (end).

[0196] Figures 15A and 15B illustrate the case where the first off-axis aberration scanner 401 and the second off-axis aberration scanner 402 perform the same operation, but the embodiment is not limited to this. If the first off-axis aberration scanner 401 and the second off-axis aberration scanner 402 do not perform the same operation, for example, if the power of the first lens group 403a and the second lens group 403b in the relay optical system 403 is different, the above-mentioned deflection control information is generated for each off-axis aberration scanner. In this case, the first off-axis aberration scanner 401 performs a deflection operation based on the first deflection control information, and the second off-axis aberration scanner 402 performs a deflection operation based on third deflection control information that is different from the first deflection control information.

[0197] Note that the processes shown in Figures 15A and 15B are merely examples of the process in step S4 of Figure 14. For example, deflection control information corresponding to off-axis aberrations other than field curvature can also be generated in the same manner as in Figures 15A and 15B.

[0198] As described above, according to the embodiment, two deflection members are positioned at optically substantially conjugate positions, and a relay optical system is positioned between the two deflection members. This forms an image at the conjugate position P in the fundus of the relay optical system that has off-axis aberrations that cancel out the off-axis aberrations of the optical systems preceding and succeeding the relay optical system, and the light from the formed image is descanned. The above scanning and descanning are performed for each type of off-axis aberration, and the fundus Ef is scanned by deflecting the descanned light with an optical scanner 60. This makes it possible to correct two off-axis aberrations (e.g., field curvature and astigmatism) with high accuracy at low cost, regardless of the eye being examined, when scanning the peripheral part of the fundus Ef, which differs from person to person, at high speed.

[0199] <Variation> (First variation) The configuration of the ophthalmic apparatus according to this embodiment is not limited to the configuration shown in Figure 1. For example, the objective optical system may include a reflective optical system. In this case, the reflective optical system guides the light deflected by the optical scanner 60 to the eye E under examination. An example of a reflective optical system is two or more curved mirrors arranged so that their reflective surfaces face each other.

[0200] The following describes an ophthalmic device according to the first modified embodiment, focusing on the differences from the ophthalmic device 1 according to the embodiment.

[0201] Figure 17 shows an example of the optical system configuration of an ophthalmic device according to a first modified embodiment. In Figure 17, the same reference numerals are used for parts that are the same as in Figure 1, and their descriptions are omitted as appropriate.

[0202] The difference between the optical system configuration of the ophthalmic device 1a according to the first modified example and the optical system configuration of the ophthalmic device 1 according to the embodiment is that an objective optical system 70a is provided instead of the objective optical system 70. In Figure 15, the objective optical system 70a is shown to include the optical scanner 60, but the objective optical system 70a does not necessarily have to include the optical scanner 60.

[0203] The objective optical system 70a includes a first concave mirror 71 as a first curved mirror and a second concave mirror 72 as a second curved mirror. The first concave mirror 71 is provided with a concave reflective surface. The second concave mirror 72 is provided with a concave reflective surface. The first concave mirror 71 is positioned so that its reflective surface faces the reflective surface of the second concave mirror 72.

[0204] In the first modified example, the first concave mirror 71 has two foci (first focal point F1, second focal point F2) that are optically approximately conjugate in position. The second concave mirror 72 has two foci (third focal point F3, fourth focal point F4) that are optically approximately conjugate in position. An optical scanner 60 (deflection surface) is positioned at or near the first focal point F1. The third focal point F3 is positioned at or near the second focal point F2. The eye under examination E (specifically, the pupil Ep) can be positioned at or near the fourth focal point F4.

[0205] The first concave mirror 71 is, for example, an elliptical concave mirror. The second concave mirror 72 is, for example, an elliptical concave mirror. The first concave mirror 71 or the second concave mirror 72 may be an aspherical mirror having a concave reflective surface. The first concave mirror 71 or the second concave mirror 72 may be a convex mirror having a convex reflective surface. The convex mirror may be an aspherical mirror.

[0206] Examples of aspherical mirrors include parabolic mirrors, hyperbolic mirrors, freeform surfaces, and mirrors whose reflective surfaces can be described by higher-order polynomials.

[0207] According to the first modification, the measurement light LS is incident on the fundus Ef of the eye under examination E at a wide angle, making it possible to acquire OCT images of the fundus Ef over a wide area. In this case, as with the embodiment, when scanning the peripheral part of the fundus Ef, which differs from person to person, at high speed, it becomes possible to correct two or more types of off-axis aberrations with high accuracy at low cost, regardless of the eye under examination.

[0208] (Second variation) In the embodiments, or the first modification thereof, a case in which the configuration of the first off-axis aberration correction optical system 40 and the configuration of the second off-axis aberration correction optical system 41 are different has been described, but the configurations in the embodiments are not limited thereto. For example, the configuration of the second off-axis aberration correction optical system 41 may be the same as the configuration of the first off-axis aberration correction optical system 40.

[0209] The following describes an ophthalmic device according to a second modified embodiment, focusing on the differences from the ophthalmic device 1 according to the embodiment.

[0210] Figure 18 shows an example of the optical system configuration of an ophthalmic device according to a second modified embodiment. In Figure 18, the same reference numerals are used for parts that are the same as in Figure 1, and their descriptions are omitted as appropriate.

[0211] The difference between the configuration of the ophthalmic device 1b according to the second modified example and the configuration of the ophthalmic device 1 according to the embodiment is that a second off-axis aberration correction optical system 41x is provided instead of the second off-axis aberration correction optical system 41.

[0212] The second off-axis aberration correction optical system 41x has the same configuration as the first off-axis aberration correction optical system 40. The second off-axis aberration correction optical system 41x includes a first off-axis aberration scanner 411x, a second off-axis aberration scanner 412x, and a relay optical system 413x. The first off-axis aberration scanner 411x (deflection plane) and the second off-axis aberration scanner 412x (deflection plane) are positioned at or near optically conjugate positions (i.e., optically approximately conjugate positions) relative to each other. In Figure 18, in the first off-axis aberration correction optical system 40, the optically approximately conjugate position is shown as "R1," and in the second off-axis aberration correction optical system 41x, the optically approximately conjugate position is shown as "R2." A fundus conjugate position P is located inside the relay optical system 413x.

[0213] In some embodiments, the first off-axis aberration scanner 411x (deflection plane) and the second off-axis aberration scanner 412x (deflection plane) are positioned at the pupillary conjugate position Q.

[0214] The first off-axis aberration scanner 411x and the second off-axis aberration scanner 412x perform deflection operations in sync with each other. More specifically, the first off-axis aberration scanner 411x and the second off-axis aberration scanner 412x perform deflection operations in sync with the deflection operation of the optical scanner 60.

[0215] In the second modification, the off-axis aberration to be compensated for in the second off-axis aberration correction optical system 41x is astigmatism, similar to the second off-axis aberration correction optical system 41. In this case, the first off-axis aberration scanner 411x and the second off-axis aberration scanner 412x are both biaxial scanners.

[0216] The first off-axis aberration scanner 411x deflects (scans) the incident measurement light LS to form an image with off-axis aberrations at the fundus conjugate position P that cancels out the astigmatism, which is an off-axis aberration of the optical systems preceding and following the relay optical system 413x. The second off-axis aberration scanner 412x descans the light from the image formed at the fundus conjugate position P.

[0217] According to the second modification, similar to the embodiment, when rapidly scanning the peripheral portion of the fundus Ef, which varies from person to person, it becomes possible to correct two off-axis aberrations (e.g., field curvature and astigmatism) with high accuracy at low cost, regardless of the eye being examined.

[0218] (Third variation) In the second modification of the embodiment, a case was described in which the configuration of the second off-axis aberration correction optical system 41a is the same as the configuration of the first off-axis aberration correction optical system 40 in the embodiment. However, the configuration of the embodiment is not limited thereto. For example, the configuration of the first off-axis aberration correction optical system 40 may be the same as the configuration of the second off-axis aberration correction optical system 41.

[0219] The following describes an ophthalmic device according to a third modified embodiment, focusing on the differences from the ophthalmic device 1 according to the embodiment.

[0220] Figure 19 shows an example of the optical system configuration of an ophthalmic device according to a third modified embodiment. In Figure 19, the same reference numerals are used for parts that are the same as in Figure 1, and their descriptions are omitted as appropriate.

[0221] The difference between the configuration of the ophthalmic device 1c according to the third modified example and the configuration of the ophthalmic device 1 according to the embodiment is that a first off-axis aberration correction optical system 40y is provided instead of the first off-axis aberration correction optical system 40.

[0222] The first off-axis aberration correction optical system 40y has the same configuration as the second off-axis aberration correction optical system 41. The first off-axis aberration correction optical system 40y includes an off-axis aberration scanner 401y and a relay optical system 403y. The relay optical system 403y, like the relay optical system 413, includes a double Gauss lens and plane mirrors 403ya, 403yb, and 403yc.

[0223] The off-axis aberration scanner 401y comprises a base, a first deflection surface 401ya provided on the first surface of the base, and a second deflection surface 401yb provided on the second surface on the back surface of the first surface of the base. In this case, the normal direction of the first deflection surface 401ya substantially coincides with the normal direction of the second deflection surface 401yb.

[0224] In some embodiments, the substrate has three or more faces, including a first face and a second face. In this case, the normal direction of the first deflection surface 401ya may intersect the normal direction of the second deflection surface 401yb.

[0225] In some embodiments, a first deflection surface 401ya is formed by providing a reflective member on the first surface. Furthermore, a second deflection surface 401yb is formed by providing a reflective member on the second surface.

[0226] The first deflection surface 401ya and the second deflection surface 401yb are positioned at or near positions that are optically conjugate to each other (i.e., optically approximately conjugate positions). In Figure 19, the optically approximately conjugate position in the first off-axis aberration correction optical system 40y is shown as "R1", and the optically approximately conjugate position in the second off-axis aberration correction optical system 41 is shown as "R2". The fundus conjugate position P is located inside the relay optical system 403y.

[0227] In some embodiments, the first deflection surface 401ya and the second deflection surface 401yb are positioned at the pupillary conjugate position Q.

[0228] Since the first deflection surface 401ya and the second deflection surface 401yb are mounted on a single base, they perform deflection operations in sync with each other. More specifically, the deflection at the first deflection surface 401ya and the deflection at the second deflection surface 401yb are performed in sync with the deflection operation of the optical scanner 60.

[0229] In the third modification, the off-axis aberration to be compensated for in the first off-axis aberration correction optical system 40y is image field curvature. In this case, the off-axis aberration scanner 401y is a single-axis scanner. In some embodiments, the off-axis aberration scanner 401y is a double-axis scanner.

[0230] The measurement light LS incident on the first off-axis aberration correction optical system 40y is deflected (scanned) by the first deflection surface 401ya of the off-axis aberration scanner 401y, thereby forming an image at the image plane position at the fundus conjugate position P between the plane mirror 403ya and the plane mirror 403yc (between the first lens group and the second lens group). At this time, the off-axis aberration scanner 401y forms an image with off-axis aberration that cancels out the image field curvature as off-axis aberration of the optical systems preceding and following the relay optical system 403y. The light from the image formed at this image plane position is descanned by the second deflection surface 401yb of the off-axis aberration scanner 401y via the second lens group and guided to the second off-axis aberration correction optical system 41.

[0231] According to the third modification, similar to the embodiment, when rapidly scanning the peripheral portion of the fundus Ef, which varies from person to person, it becomes possible to correct two off-axis aberrations (e.g., field curvature and astigmatism) with high accuracy at low cost, regardless of the eye being examined.

[0232] (Fourth variation) While the embodiments, or their first to third modifications, describe cases where two different off-axis aberrations are corrected according to the eye being examined, the configurations of the embodiments are not limited thereto. For example, the embodiments can also be applied to cases where three or more different off-axis aberrations are corrected according to the eye being examined.

[0233] Figure 20 shows an example of the optical system configuration of an ophthalmic apparatus according to a fourth modified embodiment. In Figure 20, the same reference numerals are used for parts that are the same as in Figure 1, and their descriptions are omitted as appropriate.

[0234] The difference between the configuration of the ophthalmic device 1d according to the fourth modified example and the configuration of the ophthalmic device 1 according to the embodiment is that a third off-axis aberration correction optical system 42 is added between the second off-axis aberration correction optical system 41 and the focus optical system 50.

[0235] The third off-axis aberration correction optical system 42 has the same configuration as the first off-axis aberration correction optical system 40 or the second off-axis aberration correction optical system 41, and is used to correct image field curvature and off-axis aberrations other than astigmatism (e.g., coma aberration).

[0236] The third off-axis aberration correction optical system 42 deflects the measurement light LS, which has passed through the second off-axis aberration correction optical system 41, and illuminates the lens with it, thereby forming an image with off-axis aberrations that cancels out coma aberration as an off-axis aberration of the optical system in front of (light source side) or behind (eye side) the lens at the fundus conjugate position P. Furthermore, the third off-axis aberration correction optical system 42 performs a descan operation corresponding to the scanning operation on the measurement light LS, descanning the light from the above image and guiding it to the focus optical system 50 as focused light.

[0237] According to the fourth modification, when rapidly scanning the peripheral area of ​​the fundus Ef, which varies from person to person, it becomes possible to correct three off-axis aberrations (field curvature, astigmatism, and coma aberration) with high accuracy at low cost, regardless of the eye being examined.

[0238] <Other variations> In the embodiments or modifications thereof described above, the case in which compensation is mainly provided for each type of off-axis aberration in the order of field curvature and astigmatism (or coma aberration) has been explained, but the configurations of the embodiments are not limited thereto. For example, compensation may be provided for each type of off-axis aberration in the order of astigmatism (or coma aberration) and field curvature.

[0239] In the embodiments or modifications thereof described above, the case in which the ophthalmic device has the function of an optical coherence tomography system has been explained, but the configurations according to the embodiments are not limited thereto.

[0240] In some embodiments, the ophthalmic device has the function of a scanning laser ophthalmoscope. In this case, the ophthalmic device includes an SLO optical system. The SLO optical system is an optical system that scans the fundus Ef with light using an optical scanner 60 and detects the reflected light with a photodetector. Such an SLO optical system is disclosed, for example, in Japanese Patent Application Publication No. 2018-082919.

[0241] In some embodiments, the SLO optical system obtains a frontal image of the fundus Ef by laser scanning using a confocal optical system. The SLO optical system includes an optical scanner 60, an SLO projection system that deflects light from an SLO light source via a first off-axis aberration correction optical system 40 and a second off-axis aberration correction optical system 41 using the optical scanner 60 and projects the deflected light onto the eye E under examination, and an SLO light receiving system that receives the reflected light. The optical scanner 60 can be positioned so that its deflection surface is optically approximately conjugate to the pupil Ep of the eye E under examination.

[0242] In some embodiments, the ophthalmic device functions as a slit-scan ophthalmic imaging device. That is, the light irradiated onto the eye E under examination is slit light that can be irradiated in a slit shape onto the fundus Ef. The optical scanner 60 can be positioned so that its deflection surface is optically approximately conjugate to the pupil Ep of the eye E under examination, and deflects the light descanned by the second off-axis aberration scanner 402 in a direction that intersects (specifically, orthogonal to) the longitudinal direction of the slit light.

[0243] In some embodiments, the ophthalmic apparatus comprises an illumination optical system that irradiates the fundus Ef of the eye under examination E with a slit-shaped illumination light, an optical scanner 60 (uniaxial scanner) that deflects the slit-shaped illumination light and guides it to the fundus Ef of the eye under examination E, and a photodetection optical system that receives the reflected light from the fundus Ef. The optical scanner 60 can be positioned so that its deflection surface is optically approximately conjugate to the pupil Ep of the eye under examination E. The photodetection optical system includes an image sensor whose receivable area of ​​the reflected light on the photodetection surface can be changed in accordance with the illumination area of ​​the illumination light in the fundus Ef. The image sensor is configured to read out the reception results, for example, by a rolling shutter method. Such a slit-scan type ophthalmic imaging apparatus is disclosed, for example, in International Publication No. 2022 / 124170.

[0244] [Effect] An optical scanning apparatus according to an embodiment will be described.

[0245] The first embodiment is an optical scanning device (ophthalmic device 1, 1a, 1b, 1c, 1d) configured to irradiate a measurement site (fundus Ef) in an object to be measured (eye to be examined E) with light (measurement light LS) and receive the reflected light from the measurement site. The optical scanning device includes a first aberration correction optical system (first off-axis aberration correction optical system 40, 40y), a second aberration correction optical system (second off-axis aberration correction optical system 41, 41x), and a scanning optical system (optical scanner 60). The first aberration correction optical system forms a first image having first aberrations (field curvature, off-axis aberration) at a position (fundus conjugate position P) that is optically approximately conjugate to the measurement site by scanning light, and descans the light that forms the first image. The second aberration correction optical system scans the light from the first aberration correction optical system to form a second image having a second aberration (astigmatism or coma aberration) that is different from the first aberration, at a position that is approximately optically conjugate to the measurement site (fundus conjugate position P), and then descans the light that forms the second image. The scanning optical system deflects the light descanned by the second aberration correction optical system and guides it to the object to be measured.

[0246] In this embodiment, for each type of aberration, an image with the aberration is formed at a position approximately conjugate to the measurement site by scanning the incident light, and the light forming the image is descanned. The light emitted from the final stage aberration correction optical system is deflected and guided to the object being measured. This makes it possible to correct at least two types of aberrations with high accuracy at low cost, regardless of the object being measured, when scanning the peripheral area of ​​the measurement site which differs depending on the object being measured at high speed.

[0247] In a second aspect of the embodiment, in the first embodiment, the first aberration correction optical system or the second aberration correction optical system includes a first deflection member (first off-axis aberration scanner 401, 411x), a second deflection member (second off-axis aberration scanner 402, 412x), and a relay optical system (403, 413x) disposed between the first deflection member and the second deflection member. The first aberration correction optical system or the second aberration correction optical system scans light with the first deflection member and guides it to the relay optical system to form an image with aberrations at a position that is optically substantially conjugate to the measurement site, and the light passing through the relay optical system is descanned by the second deflection member.

[0248] In this embodiment, two deflection members and a relay optical system positioned between the two deflection members can form an image with aberrations that cancel out the aberrations of the optical systems preceding and following the relay optical system at a position that is substantially conjugate to the measurement site. This makes it possible to correct at least two types of aberrations with high precision at low cost, regardless of the object being measured, using a simple configuration.

[0249] In a third embodiment of the embodiment, in the second embodiment, the first aberration or the second aberration is image field curvature.

[0250] According to this embodiment, when scanning the peripheral area of ​​the measurement site, which differs depending on the object being measured, at high speed, it becomes possible to correct at least two types of aberrations, including field curvature, with low cost and high accuracy, regardless of the object being measured.

[0251] In a fourth embodiment, in the third embodiment, the first deflection member and the second deflection member are each a uniaxial scanner.

[0252] According to this embodiment, when scanning the peripheral area of ​​the measurement site, which differs depending on the object being measured, at high speed, it becomes possible to correct at least two types of aberrations, including field curvature, with low cost and high accuracy, with even simpler control, regardless of the object being measured.

[0253] In the fifth embodiment, in the second embodiment, the first aberration or the second aberration is astigmatism or coma aberration.

[0254] According to this embodiment, when scanning the peripheral area of ​​the measurement site, which differs depending on the object being measured, at high speed, it becomes possible to correct at least two types of aberrations, including astigmatism or coma aberration, with low cost and high accuracy, regardless of the object being measured.

[0255] In the sixth embodiment, as in the fifth embodiment, the first deflection member and the second deflection member are each a biaxial scanner.

[0256] According to this aspect, regardless of the object to be measured, at least two types of aberrations including astigmatism or coma can be corrected with high accuracy through simple control.

[0257] In a seventh aspect of the embodiment, in the first aspect, the first aberration correction optical system or the second aberration correction optical system includes: a scanner (off-axis aberration scanners 411, 401y) having a first deflecting member (first deflecting surfaces 411a, 401ya) and a second deflecting member (second deflecting surfaces 411b, 401yb); and a relay optical system (413, 403y) disposed between the first deflecting member and the second deflecting member and having one or more reflecting members (plane mirrors 413a to 413c, 403ya to 403yc) that reflect light deflected by the first deflecting member. The first aberration correction optical system or the second aberration correction optical system scans light with the first deflecting member and guides the light to the relay optical system, thereby forming an image having aberration at a position substantially optically conjugate with the measurement site, and descans the light passing through the relay optical system with the second deflecting member.

[0258] According to this aspect, a single scanner and a relay optical system disposed between a first deflecting surface and a second deflecting surface provided on the single scanner can form an image having aberration that cancels the aberrations of the optical systems upstream and downstream of the relay optical system at a position substantially optically conjugate with the measurement site. This makes it possible to correct at least two types of aberrations with high accuracy at low cost regardless of the object to be measured with a simple configuration.

[0259] In an eighth aspect of the embodiment, in the seventh aspect, the scanner includes a base body. The first deflecting member is provided on a first surface of the base body. The second deflecting member is provided on a second surface that is the back surface of the first surface of the base body.

[0260] According to this aspect, synchronous control of scanning and descanning can be achieved with a simple configuration. Accordingly, it becomes possible to compensate for at least two types of aberrations that vary depending on the object to be measured at lower cost while following the high scanning speed of the measurement site.

[0261] In a ninth aspect of the embodiment, in the eighth aspect, the first aberration or the second aberration is field curvature.

[0262] According to this aspect, it is possible to compensate at least two types of aberrations including field curvature, which vary depending on the object to be measured, at lower cost while following the high scanning speed of a measurement site.

[0263] In a tenth aspect of the embodiment, in the ninth aspect, the scanner is a uniaxial scanner.

[0264] According to this aspect, with a simple configuration, it is possible to compensate at least two types of aberrations including field curvature, which vary depending on the object to be measured, at lower cost while following the high scanning speed of a measurement site.

[0265] In an eleventh aspect of the embodiment, in the eighth aspect, the first aberration or the second aberration is astigmatism or coma.

[0266] According to this aspect, it is possible to compensate at least two types of aberrations including astigmatism or coma, which vary depending on the object to be measured, at lower cost while following the high scanning speed of a measurement site.

[0267] In a twelfth aspect of the embodiment, in the eleventh aspect, the scanner is a biaxial scanner.

[0268] According to this aspect, with simple control, it is possible to compensate at least two types of aberrations, which vary depending on the object to be measured, at lower cost and with high accuracy while following the high scanning speed of a measurement site.

[0269] In a thirteenth aspect of the embodiment, in any one of the second aspect to the twelfth aspect, the scanning by the first deflecting member and the descan by the second deflecting member are configured to be executed in synchronization with the light deflection operation by the scanning optical system.

[0270] This embodiment makes it possible to compensate for at least two types of aberrations that differ depending on the object being measured, at low cost, while keeping up with the high scanning speed of the measurement area with simple control.

[0271] In the fourteenth embodiment, in the thirteenth embodiment, the deflection surface of the first deflection member and the deflection surface of the second deflection member are positioned in substantially conjugate optical positions.

[0272] This configuration makes it possible to compensate for at least two types of aberrations that differ depending on the object being measured, at low cost, while keeping up with the high scanning speed of the measurement area with relatively simple control.

[0273] In the 15th embodiment, in any of the 1st to 12th embodiments, the object to be measured is the eye to be examined (E).

[0274] According to this embodiment, when scanning the peripheral area of ​​the measurement site, which differs depending on the eye being examined, at high speed, it becomes possible to correct at least two types of aberrations with high accuracy at low cost, regardless of the eye being examined.

[0275] In the sixteenth embodiment, in the fifteenth embodiment, the scanning optical system includes a biaxial scanner (optical scanner 60) whose deflection plane can be positioned to be optically substantially conjugate with the pupil of the eye under examination.

[0276] In this embodiment, an ophthalmic device capable of illuminating the eye under examination with a wide angle makes it possible to compensate for at least two types of aberrations that differ depending on the eye under examination at low cost, while keeping up with the high scanning speed of the measurement site.

[0277] In the 17th embodiment, in the 15th embodiment, the light irradiated onto the eye under examination is slit light that can be irradiated in a slit shape onto the measurement site. The scanning optical system can be positioned so that the deflection plane is optically approximately conjugate to the pupil of the eye under examination, and the light descanned by the second aberration correction optical system is deflected in a direction intersecting the longitudinal direction of the slit light.

[0278] According to this aspect, in an ophthalmologic apparatus capable of measuring a measurement site by a slit scan method, it is possible to compensate for at least two types of aberrations that vary depending on the eye to be examined at low cost while following a high scanning speed of the measurement site.

[0279] An eighteenth aspect of the embodiment, in any one of the first to twelfth aspects, includes a focus optical system (50) disposed between a light source (10) that emits the light and a scanning optical system, and configured to change a focal position of light descanned by a second aberration correction optical system.

[0280] According to this aspect, by focusing with a position corresponding to the optical axis at the measurement site as a central portion, at least two types of aberrations are corrected in a peripheral portion away from the central portion. This makes it possible to compensate for at least two types of aberrations that vary depending on the object to be measured at low cost while following a high scanning speed of the measurement site in a wide-angle range of the measurement site.

[0281] A nineteenth aspect of the embodiment, in any one of the first to twelfth aspects, includes an interference optical system (10). The interference optical system splits light (L0) from a light source (wavelength-swept light source 11) into measurement light (LS) and reference light (LR), irradiates the measurement site with the measurement light, and detects interference light (LC) between return light of the measurement light from the measurement site and the reference light.

[0282] According to this aspect, in OCT measurement, it is possible to compensate for at least two types of aberrations that vary depending on the object to be measured. By adopting a scanner having the same specifications as the scanning means used in the scanning optical system, it is possible to compensate for at least two types of aberrations that vary depending on the object to be measured at low cost while following a high scanning speed of the measurement site.

[0283] A twentieth aspect of the embodiment, in any one of the first to twelfth aspects, includes an objective optical system (70, 70a) including a refracting optical system or a reflecting optical system. An optical scanning device guides light deflected by the scanning optical system to the object to be measured through the objective optical system.

[0284] According to this embodiment, in an optical scanning device that irradiates an object to be measured with light via a refractive or reflective optical system, it becomes possible to compensate for at least two types of aberrations that differ depending on the object to be measured at low cost while keeping up with the high scanning speed of the measurement area.

[0285] In the 21st embodiment, in the 20th embodiment, the objective optical system includes a first concave mirror (71) and a second concave mirror (72). The first concave mirror has optically substantially conjugate first focal points (F1) and second focal points (F2), and is provided with a concave first reflective surface. The second concave mirror is positioned opposite the first reflective surface and has optically substantially conjugate third focal points (F3) and fourth focal points (F4), and is provided with a concave second reflective surface. A deflection surface for light descanned by a second aberration correction optical system in the scanning optical system is positioned at or near the first focal point. A third focal point is positioned at or near the second focal point. An object to be measured can be positioned at or near the fourth focal point.

[0286] According to this embodiment, by using the first concave mirror and the second concave mirror to irradiate the object to be measured with light at a wide angle, it becomes possible to compensate for at least two types of aberrations that differ depending on the object to be measured at low cost while keeping up with the high scanning speed of the measurement area.

[0287] <Other> The embodiments described above are merely examples of how to carry out this invention. Anyone intending to carry out this invention may make any modifications, omissions, additions, etc., within the scope of the gist of this invention. [Explanation of Symbols]

[0288] 1, 1a, 1b, 1c, 1d ophthalmic equipment 10 Interferometric Optics 20 Collimator lenses 30 Optical path length correction section 40. First off-axis aberration correction optical system 41. Second off-axis aberration correction optical system 42 Third-axis off-axis aberration correction optical system 50 Focus Optics 60 Optical Scanners 70, 70a objective optical system 401 First Off-Axis Aberration Scanner 402 Second-axis off-axis scanner 403, 413 Relay Optical Systems 403a, 413d First lens group 403b, 413e Second lens group 411 Off-axis aberration scanner 411a 1st deflection surface 411b Second deflection surface 413a, 413b, 413c Plane mirror E. Eye being examined Ef fundus Ep pupil LS measurement light LR Reference Light LC interference light P Fundus conjugate position Q: Conjugate position of the pupil

Claims

1. An optical scanning device configured to irradiate a measurement site on an object to be measured with light and receive reflected light from the measurement site, A first aberration correction optical system that scans the aforementioned light to form a first image having a first aberration at a position optically substantially conjugate to the measurement site, and descans the light forming the first image, A second aberration correction optical system that scans light from the first aberration correction optical system to form a second image having a second aberration different from the first aberration at a position optically substantially conjugate to the measurement site, and descans the light forming the second image, A scanning optical system that deflects the light descanned by the second aberration correction optical system and guides it to the object to be measured, An optical scanning device including [specific components].

2. The first aberration correction optical system, or the second aberration correction optical system, First deflection member and The second deflection member, A relay optical system disposed between the first deflection member and the second deflection member, Includes, The first deflection member scans the light and guides it to the relay optical system, thereby forming an image with aberrations at a position that is optically substantially conjugate to the measurement site, and the light passing through the relay optical system is descanned by the second deflection member. The optical scanning apparatus according to feature 1.

3. The first aberration, or the second aberration, is field curvature. The optical scanning apparatus according to feature 2.

4. Each of the first deflection member and the second deflection member is a uniaxial scanner. The optical scanning apparatus according to feature 3.

5. The first aberration or the second aberration is astigmatism or coma aberration. The optical scanning apparatus according to feature 2.

6. Each of the first deflection member and the second deflection member is a two-axis scanner. The optical scanning apparatus according to claim 5.

7. The first aberration correction optical system, or the second aberration correction optical system, A scanner having a first deflection member and a second deflection member, A relay optical system having one or more reflective members disposed between the first deflection member and the second deflection member, which reflect the light deflected by the first deflection member, Includes, The first deflection member scans the light and guides it to the relay optical system, thereby forming an image with aberrations at a position that is optically substantially conjugate to the measurement site, and the light passing through the relay optical system is descanned by the second deflection member. The optical scanning apparatus according to feature 1.

8. The scanner includes a substrate, The first deflection member is provided on the first surface of the base body, The second deflection member is provided on the second surface, which is the back surface of the first surface of the base body. The optical scanning apparatus according to feature 7.

9. The first aberration, or the second aberration, is field curvature. The optical scanning apparatus according to feature 8.

10. The scanner is a single-axis scanner. The optical scanning apparatus according to feature 9.

11. The first aberration or the second aberration is astigmatism or coma aberration. The optical scanning apparatus according to feature 8.

12. The aforementioned scanner is a two-axis scanner. The optical scanning apparatus according to feature 11.

13. The system is configured such that scanning by the first deflection member and descanning by the second deflection member are performed in synchronization with the light deflection operation of the scanning optical system. The optical scanning apparatus according to any one of claims 2 to 12, characterized in that

14. The deflection surfaces of the first deflection member and the second deflection member are positioned in substantially conjugate optical positions. The optical scanning apparatus according to claim 13.

15. The object being measured is the eye being examined. The optical scanning apparatus according to any one of claims 1 to 12, characterized in that

16. The scanning optical system includes a biaxial scanner whose deflection plane can be positioned to be optically substantially conjugate with the pupil of the eye being examined. The optical scanning apparatus according to claim 15.

17. The light irradiated onto the eye under examination is a slit light that can be irradiated in a slit shape onto the measurement site, The scanning optical system can be positioned such that the deflection plane is optically approximately conjugate to the pupil of the eye being examined, and deflects the light descanned by the second aberration correction optical system in a direction intersecting the longitudinal direction of the slit light. The optical scanning apparatus according to claim 15.

18. The light source that generates the aforementioned light and the scanning optical system include a focusing optical system that is positioned between the light source and the scanning optical system and changes the focal position of the light that is descanned by the second aberration correction optical system. The optical scanning apparatus according to any one of claims 1 to 12, characterized in that

19. The system includes an interference optical system that splits light from a light source into a measurement light and a reference light, irradiates the measurement area with the measurement light, and detects the interference light between the reflected light of the measurement light from the measurement area and the reference light. The optical scanning apparatus according to any one of claims 1 to 12, characterized in that

20. Includes an objective optical system that includes a refractive optical system or a reflective optical system, The light deflected by the scanning optical system is guided to the object to be measured via the objective optical system. The optical scanning apparatus according to any one of claims 1 to 12, characterized in that

21. The aforementioned objective optical system is A first concave mirror having an optically substantially conjugate first focal point and a second focal point, and provided with a concave first reflective surface, A second concave mirror is provided with a concave second reflective surface, having a third focal point and a fourth focal point that are optically substantially conjugate, and positioned opposite the first reflective surface. Includes, A deflection plane for light that is descanned by the second aberration correction optical system in the scanning optical system is arranged at or near the first focal point, The third focal point is positioned at or near the second focal point. The object to be measured can be positioned at or near the fourth focal point. The optical scanning apparatus according to claim 20.

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