Polygonal scanning mirror aperture in ophthalmic imaging instrument

Abstract

The invention relates to a polygonal scanning mirror hole in an ophthalmic imaging instrument. An ophthalmic imaging instrument includes: a light source emitting a light beam; a polygonal scanning mirror comprising a plurality of reflective facets, each reflective facet extending in a respective first direction in a plane of rotation of the mirror and in a common, orthogonal second direction; a driver arranged to rotate the mirror such that each reflection facet reflects a light beam; an optical element that directs the reflected light beam to the eye and directs the light returning from the eye to the mirror; a detector that detects the return light reflected from the mirror; and an aperture constraining return light reaching the detector such that it is light reflected from a region of each facet extending at least one of a same first distance in its respective first direction of each facet and a same second distance in a common second direction of each facet.

Description

Technical Field

[0001] This invention relates to a polygonal scanning mirror in an ophthalmic imaging instrument. More specifically, but not exclusively, this invention relates to an aperture arranged to confine light returning from the eye in order to reduce the amount of reflected light L from each facet of the polygonal scanning mirror. R The change in quantity, the return light L R The image reaches the detector to form an image of the eye. background

[0002] Ophthalmic imaging instruments are widely used to image a patient's eye in order to assess its health. Such instruments typically include a light source and a controller arranged to control the light source to generate a beam with a target optical power. The beam is deflected by one or more scan relay elements to cover the imaging area by means of a typically parallel arrangement of multiple scan lines. The scan relay elements typically include a polygonal scanning mirror and one or more scanning galvanometer mirrors, referred to herein as "galvanometers". The former, the polygonal scanning mirror, comprises multiple reflecting facets arranged along the outer circumference of a rotating body. A actuator is operable to rotate the body of the polygonal scanning mirror such that each facet continuously reflects the incident beam at a varying angle. Thus, during the passage of a single facet, the beam is deflected by a varying angle. After such a deflection cycle is completed, the next facet essentially repeats the process, and so do all other facets.

[0003] This repeated deflection of the beam by the polygonal scanning mirror forms the basis of at least one scanning direction by providing multiple parallel scan lines. Additional scanning elements, such as the galvanometer already mentioned, can then further deflect the beam in another direction to shift the scan lines relative to each other on the target and ultimately cover the two-dimensional scan area. In at least some imaging modalities, light from the scanning beam is scattered back from the target tissue, which, in the case of ophthalmic imaging, primarily comprises parts of the human eye, such as the fundus or retina. Typically, the light thus returns along the incident light path so that it is eventually detected by a detector in the form of a light sensor, converted into an intensity signal, and processed to form an image. Specifically, this subsequent signal processing is achieved by means of computational resources that compile the individual images from the corresponding set of line scans.

[0004] Therefore, the light reflected from each facet and returning from the eye is sequentially collected by intermediate optics, detected by a detector, and used to generate an image. However, due to the manufacturing process used to produce the polygonal scanning mirror, each facet typically has slight variations in size and shape. These variations can result in different amounts of light reflected from each facet, and thus different amounts of light being collected and detected by the detector along each scan line. Consequently, the brightness of each scan line varies depending on which facet is used, due to this varying amount of collected light. This can lead to visible “banding” in the generated image, which is detrimental to image quality.

[0005] Therefore, it is necessary to control the amount of light detected by the detector along each scan line from one facet to another in order to reduce or preferably eliminate banding in the image while keeping the system complexity at an acceptable level. Overview

[0006] According to one embodiment of the present invention, an ophthalmic imaging instrument is provided. The ophthalmic imaging instrument includes a light source, a polygonal scanning mirror, a driver, optical elements, a detector, an aperture, and a pathway to computing resources. The light source is arranged to emit a light beam. The polygonal scanning mirror includes a plurality of reflective facets, each facet extending in a respective first direction in a plane of rotation of the polygonal scanning mirror and in a common second direction orthogonal to the plane of rotation of the polygonal scanning mirror. The driver is arranged to rotate the polygonal scanning mirror in the plane of rotation during operation such that each facet reflects the light beam. The optical elements are arranged to guide the light beam reflected from the polygonal scanning mirror toward the eye of a subject, and to guide light returning from the eye toward the polygonal scanning mirror. The detector is arranged to detect the returned light reflected from the polygonal scanning mirror to generate a detection signal. The aperture is arranged to constrain the returned light reaching the detector so that it is light reflected from a region on each facet, the region extending on each facet at least one of the same first distance along its respective first direction and / or the same second distance along the common second direction on each facet. The pathway is a path to computing resources arranged to generate an image of the eye using a detection signal generated by a return light reflected from at least one facet.

[0007] According to another embodiment of the present invention, a method for operating the above-described ophthalmic imaging instrument is provided. The method includes the following steps: rotating the polygonal scanning mirror by means of a driver such that each facet reflects a light beam; guiding the light beam reflected from the polygonal scanning mirror toward the eye of a subject by means of an optical element; guiding light returning from the eye toward the polygonal scanning mirror by means of an optical element; generating a detection signal by means of a detector through detecting the returned light constrained by an aperture; and generating an image of the eye using the detection signal generated from the returned light reflected by at least one facet by means of a pathway to computing resources. Brief description of the attached diagram

[0008] Embodiments of the invention will now be described with reference to the accompanying drawings, which are presented to better understand the inventive concept but should not be construed as limiting the invention. In the drawings: Figure 1 A schematic diagram of an ophthalmic imaging instrument according to a general device embodiment of the present invention is shown; Figure 2A A schematic diagram of an ophthalmic imaging instrument according to an embodiment of the present invention is shown; Figure 2B A schematic diagram of an alternative arrangement of optical elements according to an embodiment of the device is shown; Figure 3A and Figure 3B A schematic diagram of a rotating polygonal mirror and a hole according to an embodiment of the device present invention is shown; Figure 4 A schematic diagram of an ophthalmic imaging instrument according to an embodiment of the invention is shown, particularly in the context of examples of other components and optical elements; and Figure 5 A flowchart illustrating a general method embodiment of the present invention is shown.

[0009] It should be understood that, unless otherwise stated, some figures are not necessarily shown to scale. In some cases, details that are not essential for understanding this disclosure or that make other details difficult to perceive may have been omitted. Of course, it should be understood that this disclosure is not necessarily limited to the specific examples or embodiments shown or depicted herein. Detailed description

[0010] The inventors have recognized that by using apertures to constrain the amount of light reaching the detector to the amount of light reflected from a controlled-size region of each facet, the aforementioned visible “banding” in an image can be reduced or even eliminated. In this way, variations in the size and shape of the facets can be reduced or even eliminated by means of the apertures, thereby ensuring that similar or identical amounts of light reach the detector as reflected sequentially from each facet.

[0011] Example embodiments described herein will now be described with reference to the accompanying drawings.

[0012] Figure 1A schematic diagram of an ophthalmic imaging instrument 102 according to a general device embodiment of the present invention is shown. Specifically, an ophthalmic imaging system 112 is shown, which includes an ophthalmic imaging instrument 102 that provides at least one imaging modality 121, such as autofluorescence (AF), red-green, red-green-blue, and fluorescein angiography. The ophthalmic imaging instrument 102 may be or include a scanning laser ophthalmoscope (SLO) to provide one or more of at least one imaging modality 121, and may include an optical coherence tomography (OCT) device to provide an OCT imaging modality. In some embodiments, the OCT device may share one or more optical components with the SLO, such as the scanning system therein. The ophthalmic imaging system 112 may include or have (e.g., via a wired or wireless connection) access to a computing resource 106, which in turn includes a processing unit 108 and a memory unit 110. Components of an ophthalmic imaging system 112, including an ophthalmic imaging instrument 102 and computing resources 106, can be housed within a common housing, such that the system 112 thereby forms the ophthalmic imaging instrument 102, such as an ophthalmoscope. In this way, the ophthalmic imaging instrument 102 may have access to the computing resources 106, or may include the computing resources 106 itself. In some embodiments, the computing resources 106 may be located within separate housings outside the instrument 102. In some embodiments, any component may be located in a different housing than the others.

[0013] Computational resource 106 is operable to generate an image of the eye using detection signals from detectors in ophthalmic imaging instrument 102, as described later, and is operable to control and provide imaging modality 121. The computational resource has at least one processing unit 108, such as a central processing unit (CPU) and / or a graphics processing unit (GPU), and a memory unit 110 storing instructions that, when executed by at least one processing unit 108, cause the processing unit 108 to perform one or more methods and functions described herein. In embodiments of local computational resources or local physical components of a computing device, the resource may include processors (such as CPUs and / or GPUs), system memory, and a system bus coupling the system memory to the CPU / GPU. The system memory may include random access memory (“RAM”) and read-only memory (“ROM”). A basic input / output (“I / O”) system is stored in the ROM, containing basic routines such as those that facilitate the transfer of information between elements within the computing device during startup. The computational resource may also include a mass storage device capable of storing software instructions and data. Mass storage devices can be connected to the CPU / GPU via a mass storage controller connected to the system bus. Mass storage devices and their associated computer-readable data storage media can provide non-volatile, non-transitory storage for computing resource 106. While the description of computer-readable data storage media herein refers to mass storage devices such as hard disks or CD-ROM drives, those skilled in the art will understand that computer-readable data storage media can be any available non-transitory physical device or article of art from which a device can read data and / or instructions. Mass storage devices are examples of computer-readable storage devices.

[0014] Computer-readable data storage media include volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable software instructions, data structures, program modules or other data). Examples of computer-readable data storage media include, but are not limited to, RAM, ROM, EPROM, EEPROM, flash memory or other solid-state storage technologies, CD-ROM, digital versatile optical disc (“DVD”), other optical storage media, magnetic tape, magnetic tape, disk storage devices or other magnetic storage devices, or any other medium that can be used to store desired information and is accessible by a computing device.

[0015] Computing resource 106 can operate in a networked environment using a logical connection to remote network devices via a network, such as a local area network, the Internet, or another type of network. Computing resource 106 can be connected to a network via a network interface unit connected to a system bus. The network interface unit can also be connected to other types of networks and remote computing systems. Computing resource 106 includes an input / output controller for receiving and processing input from multiple other devices, including a touch user interface display or another type of input device. Similarly, the input / output controller can provide output to a touch user interface display, a printer, or other types of output devices. As described above, mass storage devices and RAM can store software instructions and data. The software instructions can include an operating system suitable for controlling the operation of computing resource 106. Mass storage devices and / or RAM can also store software instructions that, when executed by a CPU / GPU, cause computing resource 106 to provide the functionality discussed in this document, including the methods described herein and shown in the accompanying drawings.

[0016] In some embodiments utilizing the aforementioned SLO to achieve imaging modality 121, the SLO can be a confocal laser scanning microscope for diagnostic imaging of the retina of the eye. Imaging can be two-dimensional (2D) imaging, and a laser beam can be used to scan across the retina in a raster pattern to illuminate successive elements of the retina point-by-point. Light reflected from each retinal point can be captured by a photomultiplier tube. The output of the photomultiplier tube can be recorded and displayed in a digital format. In this way, the SLO may be able to produce high-contrast, detailed images of the retina. In some embodiments, images are captured sequentially using one imaging modality of the SLO and at least one additional imaging modality using at least one of the SLO and an OCT device.

[0017] Figure 2A A schematic diagram of an ophthalmic imaging instrument 102 according to an embodiment of the present invention is shown. As shown, the ophthalmic imaging instrument 102 includes a light source 200, which is arranged to emit a light beam 201 as a scanning beam. A polygonal scanning mirror 202 serves as a first scanning element (or in other words, a first scanning relay) and is arranged about a rotation axis a. xThe polygonal scanning mirror 202 rotates in a plane of rotation (i.e., parallel to the yz plane). The polygonal scanning mirror 202 includes (e.g., having the same shape) a plurality of reflective facets 2021, 2022... Each reflective facet extends in a respective first direction in the plane of rotation of the polygonal scanning mirror 202 (i.e., the direction defining the edge of the polygonal shape of the polygonal scanning mirror in the yz plane) and in a common second direction orthogonal to the plane of rotation of the polygonal scanning mirror 202 (i.e., the common x-direction of all facets among the plurality of facets). In some embodiments, the beam 201 may have a cross-sectional area that is a fraction of the area of ​​the facets (e.g., less than 0.1% or 1% of the area of ​​each facet). The polygonal scanning mirror 202 is arranged to reflect the beam 201 toward the optical element 204 and return the light L from the eye E. R The beam 201 reflects toward detector 205, as described later. As shown, when incident on polygonal scanning mirror 202, the beam 201 may have a component in a direction opposite to the positive y-direction during its travel. In this embodiment, the polygonal scanning mirror is a regular convex polygon with six rectangular facets, each facet having a length defined by the lengths of two edges of the polygonal scanning mirror 202 parallel to its plane of rotation in a respective first direction, and a width defined by the lengths of two edges of the polygonal scanning mirror 202 orthogonal to the plane in a common second direction. However, other numbers of facets (e.g., 16 facets or at least four or five facets), facet shapes, or polygonal geometry may be used alternatively.

[0018] A driver 203 is arranged to rotate the polygonal scanning mirror 202 during operation (in the plane of rotation of the polygonal scanning mirror 202) such that each facet 2021, 2022... reflects the light beam 201 at a varying angle α (as the facets rotate at angular positions within a predetermined range). The driver 203 may be, for example, a motor connected to the polygonal scanning mirror 202 and controlled by a controller (which may be computing resource 106) of the ophthalmic imaging instrument 102. As shown, the path of the scanning light beam 201 is illustrated in a one-dimensional (1D) scan generated during an exemplary counterclockwise rotation of the polygonal scanning mirror 202 (indicated by a curved arrow). Path "A" is an example of the scanning light beam 201 reflected from the corresponding facet 2021 of the polygonal scanning mirror 202 at the starting point during rotation (i.e., when facet 2021 moves into the path of the light beam 201 from the light source 200). Path "B" is an example of a scanning beam 201 reflected from the corresponding facet 2021 of the polygonal scanning mirror 202 at a later time point after further downward rotation, as facet 2021 moves out of the path of the beam 201 from the light source 200.

[0019] In this manner, as the beam 201 moves from one edge of a facet defining its length to another, the polygonal scanning mirror 202 reflects the beam 201 from the active facet (i.e., the facet currently reflecting the beam 201 from the light source 200 to the optical element 204) at (or by) a varying angle α. When facet 2021 moves out of the range of the beam 201, the adjacent facet 2022 (i.e., the facet adjacent to / bordering facet 2021 in a rotational direction opposite to the rotational direction of the polygonal scanning mirror 202) substantially repeats the described reflection process, such that each facet sequentially reflects the beam 201 continuously at a varying angle α. This varying angle α varies with the control of the length and rotation of the respective facet, and the corresponding orientation of the facet relative to the incident beam 201 determines the reflection angle of the beam 201. The varying angle α includes a varying angle β as part of the varying angle α. In this embodiment, the changing angle β may be different from the changing angle α, and more specifically, it may be a subset of the changing angle α (e.g., greater than 50%, 70%, or 90% of the changing angle α and less than 95% or 100% of the changing angle α, centered within the changing angle α).

[0020] The ophthalmic imaging instrument 102 also includes an optical element 204 arranged to guide a light beam 201 reflected from the polygonal scanning mirror 202 (i.e., a light beam 201 reflected at a varying angle α) toward the subject's eye E. Figure 2A As shown, optical element 204 is arranged such that when beam 201 is reflected by polygonal scanning mirror 202 through the entire changing angle α, beam 201 is reflected toward the subject's eye E. Additional components and optical elements such as optics 290 may be arranged between optical element 204 and the subject's eye E, as will be discussed later. Figure 4 The optical element 204 may be or include a curved mirror (e.g., an ellipsoidal mirror), as shown, with the activated facet at one of its focal points, but the optical element 204 may also take any other suitable form. Embodiments considering curved mirrors are explained in more detail elsewhere in this disclosure.

[0021] Optical element 204 is also arranged to receive light L returning from eye E. R Guided towards polygonal scanning mirror 202. Return light L R This can be, for example, light scattered from the eye E in a red-green or red-green-blue imaging mode, or it can be or include, for example, light emitted from the eye E in an AF imaging mode. The returning light L R Following the same optical path as beam 201, it can therefore be reflected by optical element 204 at a varying angle α toward polygonal scanning mirror 202 along the optical path corresponding to the reflection of beam 201. (Return to light L) RTherefore, the light is guided by optical element 204 to the activation surface, and the activation surface reflects the reflected light L along the optical path of beam 201 toward detector 205. R This is done to form an image 210 of the eye E, as described below. When the currently active facet moves outside the range of the beam 201, the adjacent facet becomes the active facet and essentially repeats the return light L. R The described reflection process causes each facet to reflect the returned light L sequentially along the optical path of beam 201 toward detector 205. R Therefore, continuous scan lines in image 210 can be formed by using, for example, orthogonal scanning elements, as described later. In some embodiments, the return light L from the eye E R The beam can be larger than the diameter of beam 201 and can be (substantially) equal to the diameter of the pupil of eye E. The beam can have a size that (substantially) fills the entire area of ​​each facet. However, those skilled in the art will understand, for example, that this depends on additional components and optional elements 290..., the characteristics of beam 201, the location of beam 201 incident on eye E, and imaging mode 121.

[0022] Figure 2B A schematic diagram of an alternative arrangement of the optical element 204 is shown. In this alternative arrangement, the optical element 204 guides the beam 201 reflected from the polygonal scanning mirror 202 (i.e., the beam 201 reflected at the changing angle α) toward the subject's eye E only during the rotation of the polygonal scanning mirror 202, which corresponds to a portion β of the changing angle α for each facet. That is, when the polygonal scanning mirror 202 reflects the beam 201 at the changing angle α, the beam 201 is reflected toward the subject's eye E only when the polygonal scanning mirror 202 reflects the beam 201 at the changing angle β, due to the angle of the arc of the optical element 204. Path "C" is an example of the beam 201 when it first incident on the optical element 204 from the active facet as the polygonal scanning mirror 202 rotates. Path "D" is an example of the beam 201 when it finally incident on the optical element 204 from the active facet 2021 as the polygonal scanning mirror 202 rotates. Outside of this changing angle β, the beam L... B Therefore, no light is incident on the optical element 204, and thus does not reach the eye E. Consequently, no light, or a negligible amount thereof, may return from the eye E toward the polygonal scanning mirror 202 for detection by the detector 205.

[0023] As described above, the reflection process is repeated continuously during the operation and rotation of the polygonal scanning mirror 202, thus different individual facets form each successive scan line. Therefore, the ophthalmic imaging instrument 102 also includes an aperture (i.e., opening) 206, which is arranged to constrain (or limit) the reflected light L reaching the detector 205.R This is such that it is reflected (only) from the same size (and same shape) region of each facet during rotation of the polygonal scanning mirror, corresponding to a change in angle α for each facet (e.g., the same portion β). In other words, the aperture 206 is arranged to block some of the returning light L from the eye E. R This ensures that during the rotation of the portion β of the polygonal scanning mirror 202 corresponding to the change in angle α for each facet, the reflected light L from each facet... R Regardless of the size of the corresponding facet. Therefore, when the reflection process is repeated, each facet reflects the beam 201 at a varying angle α, and when the facet reflects the beam 201 at a varying angle β, the aperture 206 constrains the return light L reaching the detector 205. R This is done so that the light beam 201 is reflected from a region of the same size on the facets. Therefore, the polygonal scanning mirror 202 includes multiple angular rotations per revolution, each angular rotation corresponding to the polygonal scanning mirror 202 reflecting the light beam 201 onto the facets of the multiple facets by a varying angle β. As those skilled in the art will understand, Figure 2A The symmetrical arrangement of the polygonal scanning mirror 202 and the aperture 206 in the design ensures that the portion β of the changing angle α is the same for each facet, although the corresponding portion β of the changing angle α for each facet may differ depending on the size and shape of the facets and their relative orientation with respect to the aperture 206 and the beam 201. Regions of the same size extend the same first distance along their respective first direction on each facet and extend the same second distance along a common second direction on each facet.

[0024] Therefore, the use of aperture 206 ensures that during the rotation of the portion β of the polygonal scanning mirror 202 corresponding to the change in angle α for each facet, the amount of light detected by detector 205 will be the same, regardless of which facet currently reflects the beam 201 (and the returning light L). R This is irrelevant. As described later, this could lead to detector 205 detecting different amounts of light to form an image of the eye E, a variation in the size of each facet, which is eliminated by using aperture 206 during rotation of the polygonal scanning mirror 202 at an angle α corresponding to the variation of each facet. The returned light L detected during rotation of the polygonal scanning mirror 202 corresponding to the angle α corresponding to the variation of each facet is also affected. R The scan lines formed by the scan lines can produce images that do not show visual "banding" or show significantly reduced visual "banding", and thus can greatly improve the quality of the image.

[0025] Figure 3AAn enlarged schematic diagram of the rotating polygonal mirror 202 together with aperture 306 is shown. As in this embodiment of the device, aperture 306 may be aperture 206. These components are shown together with additional optional elements that may form part of ophthalmic imaging instrument 102, as described below. Aperture 306 is arranged such that the beam 201 and the returning light L... R The light passes through it to be reflected from each facet of the polygonal scanning mirror 202. The aperture 306 is also arranged to direct the returning light L... R The light is projected onto an area of ​​the same size on each facet so that it is reflected from the same area on each facet during the rotation of the polygonal scanning mirror 202, which corresponds to a portion β of the angle α that varies with each facet. The aperture 306 then blocks some of the reflected light L. R Reflection from the facets ensures that only the returning light L is reflected from regions of the same size on the facets. R Arrive at detector 205, as described later.

[0026] like Figure 3B The diagram illustrates a rotating polygonal mirror 202 and hole 306 in the xy-plane when the (activated) facet 2021 is arranged parallel to hole 306. Hole 306 is rectangular in plane 308 (parallel to the xy-plane). Hole 306 has a length defined by the lengths of its two edges 306-3 and 306-4 parallel to the plane of rotation, and a width defined by the lengths of its two edges 306-1 and 306-2 orthogonal to the plane of rotation. A line orthogonal to plane 308 of hole 306 and passing through the center of hole 306 intersects the rotation axis a of polygonal scanning mirror 202. x The facets intersect and are parallel to the plane of rotation of the polygonal scanning mirror 202. Furthermore, each facet is parallel to the plane 308 of the aperture 306 at a given rotation of the polygonal scanning mirror 202 when reflecting the beam 201. However, those skilled in the art will understand that other geometries and arrangements of the aperture 306 can be used alternatively. As in this embodiment, the aperture 306 can be in a plate 307 (i.e., a hole in plate 307), although it can alternatively be formed in a sheet or the like. The component forming the aperture 306 can be mounted within the ophthalmic imaging instrument 102 (e.g., mounted to the housing of the ophthalmic imaging instrument 102). In some embodiments, when the facet 2021 moves into the path of the beam 201 from the light source 200, the plate 307 can block the beam 201 reflected at a varying angle α for a portion of the angle α. In this case, the portion β of the varying angle α may not include said portion of the varying angle α, because no light or a negligible amount thereof can return from the eye E toward the polygonal scanning mirror 202 to be detected by the detector 205 (because the beam 201 is not incident on the eye E).

[0027] like Figure 3B As further shown in the diagram, the return light L reaches detector 205. RIt is the light projected onto and reflected from the central region 2021(A) on the facet 2021, which is a region of the same size (and shape) for each facet. The central region 2021(A) extends the same first distance 224 in a corresponding first direction d1 (in this case, the y direction) on the facet 2021, and extends the same second distance 225 in a common second direction d2 (x direction) on the facet 2021. The central region 2021(A) is surrounded by the outer peripheral region 2021(B) (in... Figure 3B (As shown by the dashed line). The shape of the central region 2021(A) is determined by the shape of the aperture 206, and in this case it is rectangular. Due to the angle of the beam 201 and the return beam L... R At the angle, the central region 2021(A) is smaller than the size of the hole 306. That is, in this orientation of facet 2021, the upper surface of the plate 307 forming the hole 306 blocks the reflected light L. R The reflected light L is reflected from the facet 2021 below the central region 2021(A) and from the facet 2021 above the central region 2021(A). R It is blocked by the lower surface of plate 307 and cannot reach detector 205.

[0028] During the rotation of the polygonal scanning mirror 202, corresponding to the portion β of the changing angle α of the facet 2021, the central region 2021(A) on the facet 2021 moves between the first boundary 220 and the second boundary 221 on the facet 2021. Although the central region 2021(A) is within these boundaries, its size (and shape) is the same for the equivalent angular rotation of the polygonal scanning mirror 202 (i.e., the equivalent angle within the changing angle β corresponding to each facet), regardless of which facet the region is formed on. These boundaries 220, 221 are first predetermined distances 223 from the edges 2021-1, 2021-2 that define the width of the facet 2021, but alternatively, the boundaries 220, 221 can be different distances from their respective nearest edges among these edges 2021-1, 2021-2.

[0029] This movement of the central region 2021(A) is repeated as the polygonal scanning mirror 202 rotates so as to reflect the returned light L from the next facet 2022 (not shown). R In this way, the central region of each facet can be greater than or equal to a predetermined distance from the edge of the facet, which can be, for example, 0.1%, 1%, or 10% of the width or length of the facet. Figure 3BAs shown, for facet 2021, during the rotation of the portion β of the polygonal scanning mirror 202 corresponding to the change in angle α of facet 2021, the central region 2021(A) is greater than or equal to a first predetermined distance 223 from the edges 2021-1, 2021-2 defining the width of facet 2021, and greater than or equal to a second predetermined distance 222 from the edges 2021-3, 2021-4 defining the length of facet 2021. Therefore, the central region 2021(A) maintains a distance greater than or equal to the smaller of the first predetermined distance 223 and the second predetermined distance 222 (or greater than or equal to both if the first predetermined distance 223 and the second predetermined distance 222 are the same). More generally (e.g., for other facet shapes), the interval (or gap) between the central region 2021(A) of each facet and the periphery of the facet is greater than or equal to the predetermined distance. In this case, the predetermined distance may be 0.1%, 1% or 10% of the distance by which the facet extends over at least one of its respective first direction and / or common second direction.

[0030] By ensuring that during the rotation of the portion β of the polygonal scanning mirror 202 corresponding to the change in angle α of the facet, the central region of each facet is greater than or equal to a predetermined distance from the periphery of the facet, the aperture 206 constrains the return light L reaching the detector 205. R This ensures that the light is reflected from a region of the same size on each facet, since this region is far from the edge of the facet on each facet. Therefore, even if there are differences in the size of the facets (e.g., length or width), the reflected light will not be affected. R The size difference of the regions ensures that the amount of light collected by detector 205 will be the same regardless of which facet is active, as described above. Furthermore, a predetermined distance from the edge of the facet can be set to avoid regions in the outer periphery of each facet that may contain variations in facet reflectivity, for example, due to the manufacturing process used to produce the polygonal scanning mirror 202, which can further improve image quality.

[0031] return Figure 3A The ophthalmic imaging instrument 102 also includes an optional housing 208 with an opening 209, which surrounds the rotating polygonal mirror 202. In such an embodiment, the housing 208 can protect the ophthalmic imaging instrument 102 from malfunctions of the rapidly rotating polygonal scanning mirror 202 by containing fragments of the polygonal scanning mirror 202 that may be propelled outward at high speed. With the optional housing 208 provided, a plate 307 forming an aperture 306 is attached to the housing 208 through the opening 209 to align the aperture 306 and the opening 209 (e.g., their centers). Thus, the beam L... B and return light LR Both aperture 306 and opening 209 can pass through to reflect light from each facet of the polygonal scanning mirror 202. However, without housing 208, plate 307 can be attached to ophthalmic imaging instrument 102 in other ways, such as to the aforementioned housing of ophthalmic imaging instrument 102. As in this device embodiment, opening 209 can be larger than the size of each of the plurality of facets in order to unconstrain or negligibly constrain (or limit) the return light L reflected from each (activated) facet reaching the detector. R However, in some embodiments, the hole 206 can be provided through the opening 209, and therefore can be directly implemented by the housing 208, in order to reduce the number of components in the ophthalmic imaging instrument.

[0032] The ophthalmic imaging instrument 102 (or more specifically, opening 209) also includes an optional phase mask 210, which can be arranged to cover opening 209. Phase mask 210 can correct for aberrations caused by at least one of optical element 204 and components and optical elements 290, as described later, such as scanner surfaces and ellipsoids, as described later.

[0033] Although the above describes that aperture 306 is arranged such that beam L B and return light L R It reflects light from each face of the polygonal scanning mirror 202, and the returned light L R The light is projected onto an area of ​​the same size on each facet so that it is reflected from the same area of ​​the same size on each facet during rotation of the polygonal scanning mirror 202, which corresponds to a portion β of the angle α that varies with each facet. However, the invention is not limited thereto. For example, in some embodiments, aperture 206 (or aperture 306 thereof) may alternatively be placed within the path of the beam 201 between the polygonal scanning mirror 202 and the light source 200 in order to constrain the return light L reaching the detector 205. R This is so that it is reflected from the same-sized region of each facet during the rotation of the polygonal scanning mirror 202, which corresponds to the portion β of the angle change corresponding to each facet. In other words, without first returning light L... R In the case of projection onto an area of ​​the same size on each facet (return light L) R Therefore, in this case, the light incident on the entirety of each facet (the aperture 206 blocks the reflected light L from the outside of the same-sized area of ​​each facet) R The beam reaches detector 205. In this case, aperture 206 can be, for example, a circular aperture coaxial with beam 201.

[0034] Furthermore, although the above description of aperture 206 (and its example aperture 306) constrains the return light L reaching detector 205 RThis is to ensure that the light is reflected from areas of the same size (and shape) on each facet, but the invention is not limited thereto. More generally, the aperture 206 may be arranged to constrain (or limit) the return light L reaching the detector 205. R The light beam 201 and the return light L are reflected (only) from a region on each facet that extends at least one of a first distance along a corresponding first direction on each facet and / or a second distance along a common second direction on each facet. That is, a region on each facet may extend a first distance along a corresponding first direction on that facet, and this first distance is the same on all facets, and a region on each facet may extend a second distance along a common second direction on each facet, and this second distance is the same on all facets. As described above, the aperture 206 can be similarly arranged such that the light beam 201 and the return light L... R It reflects light from each facet of the polygonal scanning mirror 202, and the returned light L R The projection is onto the region of each facet so that it is reflected from the region of each facet (in some cases, this may be during the rotation of the polygonal scanning mirror 202, which corresponds to the portion β of the angle α that changes with each facet).

[0035] Therefore, in addition to the above example of hole 306, hole 206 can also be, by way of example only: a slot in a plate extending in the y-direction (e.g., replacing hole 306 on plane 308) to constrain the return light L reaching detector 205 in a common second direction on each facet along the entire range (i.e., the length of the facet) in the corresponding first direction on each facet. R However, it does not restrict the return light L reaching the detector 205 in the corresponding first direction on each facet. R ; or a slot in a plate extending in the x-direction (e.g., replacing hole 306 on plane 308) to constrain the return light L reaching the detector in the corresponding first direction of each facet along the entire range of the second direction (i.e., the width of the facet) of each facet. R However, it does not restrict the return light L reaching detector 205 in the common second direction on each facet. R In this way, the aperture 206 can constrain the return light L reaching the detector 205 during the rotation of the polygonal scanning mirror 202. R In order to reduce the amount of reflected light L reaching detector 205 from each facet 2021, 2022, ... R The amount varies between multiple facets 2021, 2022, ... By reducing this variation, the returned light L corresponding to each detected facet is... R The scan lines formed by the scan lines can exhibit reduced visual "banding" in the image, and thus improve the image quality.

[0036] As another example, in the case where hole 206 is a slot in a plate extending along the y-direction, Figure 3B In this process, the central region 2021(A) will instead extend from edge 2021-1 to edge 2021-2 of the facet 2021 in the corresponding first direction d1. Therefore, the aperture 206 can constrain the return light L reaching the detector 205. R This is to ensure that the image is reflected from a region extending the same second distance 225 along a common second direction d2 on each facet, which can therefore reduce or eliminate variations in the width of each facet that may occur due to the manufacturing process, in order to reduce or remove visible “stripes” in the image, as previously described.

[0037] Return to Figure 2A Detector 205 is arranged to detect reflected light L from the polygonal scanning mirror 202 (i.e., from one or more facets). R To generate detection signal S d Therefore, the presence of aperture 206 causes detector 205 to detect reflected light L from regions of the same size on each facet, or, in the more general case described above, reflected from regions on each facet. R As described above, the detection signal S d The signal is sent to and received by computing resource 106 via path 207 to computing resource 106. Detector 205 may comprise a one-dimensional or two-dimensional array of photosensitive elements. However, the form of detector 205 is not limited, and detector 205 may, for example, comprise a balanced photodetector arrangement comprising two reverse-biased photodiodes whose output photocurrents are subtracted from each other, and the subtracted current signal is converted into a voltage detection signal by a transimpedance amplifier.

[0038] Path 207 is a path to computing resource 106, which is arranged to use a return light L reflected by at least one facet (and detected by detector 205). R The generated detection signal S d An image 210 of the eye E is generated. As in this embodiment of the device, the detection signal S is used. d It can be during the rotation of the polygonal scanning mirror 202, which corresponds to a portion β of the angle α corresponding to the change of at least one facet, from the returning light L R The generated signals, although as described below, are not necessarily so. Thus, the image 210 of eye E is generated by each corresponding to the detection signal S. d The continuous scan lines are formed, and the detection signal S dThe reflected light L is detected during the rotation of the polygonal scanning mirror 202, which corresponds to the portion β of the angle α that varies with each facet. R Therefore, the amount of light detected by detector 205 will be the same for each scan line, regardless of which facet currently reflects the beam 201, as described above, because in each scan line, the returned light L... R It is reflected from a region of the same size as the facet. In other words, computing resources 106 are arranged to reflect the returning light L from a region of the same size as the facet. R An image 210 of the eye E is generated. In some embodiments, the image 210 of the eye E is generated using a detection signal S. D The generated detection signal S D The reflected light L is the portion of the polygonal scanning mirror 202 whose facets are rotated at an angle α corresponding to the change of the facets. R Generation. In other words, image 210 includes scan lines that correspond to, respectively, the reflected light L from each facet of the polygonal scanning mirror 202 during rotation of the polygonal scanning mirror 202, corresponding to a portion β of the angle α that varies with each facet. R .

[0039] exist Figure 2A In the arrangement, the detection signal S d The reflected light L can be detected during the rotation of the polygonal scanning mirror 202, which corresponds to the entire change in angle α (and therefore includes part of β). R Therefore, the path 207 to computing resource 106 can be ignored or discarded by the following return light L. R The generated detection signal S d The reflected light from the at least one facet during the rotation of the polygonal scanning mirror 202, which is at an angle α that does not correspond to a change in angle α of at least one facet. Therefore, the detection signal S used to generate the image 210 of the eye (E) d It is generated during the rotation of the polygonal scanning mirror 202, which corresponds to the portion β of the angle α corresponding to the change of at least one facet, and therefore the image 210 uses only the reflected light L from the same size area of ​​at least one facet, or, in the more general case described above, the reflected light L from the area of ​​at least one facet. R The generated detection signal S d To generate.

[0040] exist Figure 2B In the alternative arrangement, outside the changing angle β, the beam 201 does not reach the eye E, and therefore no light is returned for detection by the detector 205, as previously described. Therefore, no detection signal S is detected during the rotation of the portion of the polygonal scanning mirror 202 corresponding to the changing angle α outside the changing angle β.d The only detection signal S is generated. Therefore, the only signal used by the pathway 207 to the computing resource 106 to generate the image 210 is... d The reflected light L is from a region of the same size on at least one facet, or, in the more general case described above, from a region on at least one facet. R Generated.

[0041] The return light L reaches the detector 205 under the constraint of aperture 206. R In such a case that the light is reflected from a region on each facet (which extends the same second distance along a common second direction on each facet), the path 207 to computational resource 106 can alternatively use the reflected light L from at least one facet (and detected by detector 205) during rotation of the polygonal scanning mirror 202 at an angle α corresponding to a change in at least one facet. R The generated detection signal S d To generate an image 210 of the eye E. That is, in this case, a portion β of the changing angle α can be 100% of the changing angle α. In this way, each successive scan line in image 210 can correspond to the reflected light L detected during the rotation of the polygonal scanning mirror 202 corresponding to the entire changing angle α of each facet. R The generated detection signal S d This allows for an extended field of view of the ophthalmic imaging instrument 120 (by utilizing the entire length of each facet when reflecting the beam 201), while at least partially suppressing visual “stripes” in the image.

[0042] Figure 4 A schematic diagram of an ophthalmic imaging instrument 120 according to an embodiment of the present invention is shown, particularly in the context of examples of other components and optical elements 290, etc., and again, elements as explained in conjunction with Figure 2, etc., are shown (the same reference numerals therefore denote the same elements and functions). As mentioned above, it may also include... Figure 3AThe optional components shown are described. An ophthalmic imaging instrument 120 is described in the context of an imaging modality in which a beam 201 is generated by a light source 200 and guided toward a patient's eye E, reflected at the tissue of the eye E, and guided back to a detector 205. As part of an SLO module, the instrument 120 includes a light source 200 that emits the beam (i.e., the scanning beam 201) and a plurality of scanning relay elements. The scanning relay elements include a first scanning element in the form of a polygonal scanning mirror 202, a second scanning element 206, and an optical element positioned and configured to guide the scanning beam 201. In some embodiments, the optical element may include an optical element 204 and a second optical element 208, where the optical element 204 may be a scan compensation element, such as a curved mirror or a slit mirror, and the second optical element 208 may be a scan transfer element, such as a primary mirror.

[0043] Optical elements 204 and 208 are positioned and configured to guide the scanning beam 201. The second scanning element 206 may be or include an oscillating plane mirror or a plane mirror coupled to a galvanometer motor. Optical element 204 may be a curved mirror, such as an ellipsoidal mirror. The second optical element 208 may be an aspherical mirror. It should be understood that the first and second optical elements may have alternative forms. Scanning elements 202 and 206 may be referred to as a scanning device or multiple separate scanning devices. It should be understood that the functions shown are merely examples of configurations that can be used with the embodiments described herein. In some examples, one or more of the scanning elements may include, for example, one or more of an oscillating plane mirror, a galvanometer mirror, a MEMS mirror, a rotating mirror, a prism, or a polygonal scanner and / or a resonant mirror.

[0044] As described above, hole 206 is provided and configured to constrain the return light L. R During the rotation of the polygonal scanning mirror 202, which corresponds to the portion β of the angle α that varies with each facet, reflections are made from the same sized region of each facet of the rotating polygonal mirror 202.

[0045] In some examples, detector 205 may be a separate component or device operatively coupled to light source 200, such that detector 205 and light source 200 may be positioned in the same location or adjacent to each other. In some examples, light source 200 may be implemented together with detector 205 as a single device or a device within a common housing, such that, in addition to emitting scanning beam 201, the device may also be able to detect or receive light, such as light reflected from first scanning element 202 or from optical element 204. In some further examples, ophthalmic imaging instrument 120 may include a focusing lens positioned in front of detector 205, the focusing lens being arranged to focus all or substantially all of the returned light L constrained to detector 205 by aperture 206. R .

[0046] In the exemplary SLO imaging mode, the scanning beam 201 can be a laser of a suitable wavelength used in SLO applications. If other imaging modes are included, the scanning beam 201 can be a collimated beam, comprising, for example, a laser for SLO applications and a superluminescent diode (SLD) for other applications. It should be understood that any suitable collimated light source can be used, such as a single-frequency laser diode, a vertical-cavity surface-emitting laser, a wavelength-scanning laser source, a pulsed laser source, or other light sources with sufficient intensity and good collimation to produce sufficient retinal illumination. In such applications, an SLD can be used due to the short coherence length required to distinguish the retinal layer from the resulting interferometric data. The SLD can be free-space coupled to the scanning system or fiber-coupled to the scanning system via standard or polarization-maintaining fibers. A frequency-scanning laser source can also be used in other applications, thereby tuning the wavelength of the source within a given range.

[0047] In some embodiments, each of the first scanning element 202 or the second scanning element 206 may be a single element or an arrangement of two or more elements, as long as it is suitable for providing a scan at a corresponding focal point F1 or F2 (as shown) where the scanning elements are positioned. Focal points F1 and F2 are the focal points of optical element 204, and focal points F2 and F3 are the focal points of optical element 208. The first scanning element 202 is located at focal point F1, the second scanning element 206 is located at focal point F2, and the eye E (e.g., the pupil of eye E) is located at focal point F3 (also referred to as a virtual scan point). When light sweeps across the virtual scan point (e.g., across F3) onto the eye E (e.g., onto the fundus of eye E), the resulting scan may be a 2D scan of the scanning beam 201 or a scan pattern.

[0048] In some embodiments, the first scanning element 202 provides a vertical, horizontal, or patterned scan incident on the optical element 204 to a point on the second scanning element 206 via the optical element 204. For example, the scan can be a 1D or 2D optical scan. The axes of the first scanning element 202 and the second scanning element 206 can be arranged to create a 2D optical scan, such as in the form of a raster scan pattern of a scan beam 201. The alignment of the first scanning element 202 and the second scanning element 206 can be orthogonal, substantially orthogonal, or arranged to produce any scan geometry around the optical elements 204 and 208.

[0049] In some embodiments, the second scanning element 206 provides various scans, such as 1D or 2D optical scans, which may include horizontal scans, vertical scans, or any pattern of the scanning beam 201. The scans provided by the first scanning element 202 and the scans provided by the second scanning element 206 differ from each other, for example, with respect to the orientation of the scans. In some examples, one of the scanning elements may provide a vertical scan of the retina, and the other scanning element may provide a horizontal scan of the retina. The scanning beam 201 is guided toward the eye E via the scanning elements 202 and 206 and the optical elements 204 and 208, such that a wide or ultra-wide field of view scanning angle is achieved, for example, at the pupillary plane of the eye E.

[0050] A "wide field of view" scan refers to a scanning angle exceeding 50 degrees in one or two dimensions. An "ultra-wide field of view" scan refers to a scan that essentially covers the entire retina of the eye E. In some examples, multiple line scans can be generated by scanning the retina along a first direction using a first scanning element 202, and by changing the position of the multiple line scans along a second direction using a second scanning element 206, wherein the second direction is orthogonal to the first direction. Figure 4 As shown, the path of the scanning beam 201 is illustrated in a 1D scan generated by a single oscillation or rotation (indicated by the curved arrow) of the first scanning element 202. Path "A" is an example of the scanning beam 201 reflected from the polygonal scanning mirror at one orientation of the reflective facet during rotation, while paths "B" and "C" are examples of the scanning beam 201 reflected at other orientations of the facet during rotation.

[0051] The components of the ophthalmic imaging instrument 120 can be arranged such that the axis of rotation of the first scanning element 202 is substantially parallel to the line connecting the two focal points (i.e., F2 and F3) of the optical element 208, such that the scanning beam 201 scans across the secondary axis of the optical element 204. Furthermore, the first scanning element 202 can produce a 1D or 2D scan incident on the optical element 204. Therefore, the optical element 204 can also produce a 1D or 2D scan. The components of the ophthalmic imaging instrument 102 can be arranged such that the line connecting the two focal points (i.e., F2 and F3) of the optical element 208 lies substantially on the plane defined by the scan produced by the optical element 204 (e.g., a 1D vertical scan).

[0052] Therefore, the first scanning element 202 and the second scanning element 206 can work together to create an optical scan in the form of a raster scan pattern, such as a 2D scan, from a single point in space at or near the focal point F3 in the patient's eye E. The first and second scanning elements can have operating parameters including the amplitude and rotational offset of the oscillation. The operating parameters also include the oscillation speed. Both operating parameters can be selected to control the direction and pattern of the optical scan from the surface point light source. In some examples, the first and second scanning elements can be housed in a rotatable mount (not shown) that can adjust the centering (or eccentricity) of the scanning beam 201 on the retina of the eye E, providing the ability to “move” the imaging field across the retina.

[0053] Figure 5 A flowchart of a general method embodiment of the present invention is shown. Specifically, the method embodiment relates to operating an ophthalmic imaging instrument including a light source, a polygonal scanning mirror, optical elements, a detector, an aperture, and a pathway to computing resources. For example, the method may be adapted to operate an ophthalmic imaging instrument 102 as disclosed and described in conjunction with embodiments of this disclosure. The method includes: step S101, rotating the polygonal scanning mirror by means of a driver such that each facet reflects a light beam (at a varying angle); step S102, guiding the light beam reflected from the polygonal scanning mirror (at a varying angle) toward the eye of a subject by means of optical elements; step S103, guiding light returning from the eye toward the polygonal scanning mirror by means of optical elements; step S104, generating a detection signal by means of a detector through detecting the returned light constrained by the aperture; and step S105, generating an image of the eye using the detection signal generated from the returned light reflected from at least one facet (during rotation of the polygonal scanning mirror corresponding to a portion of the varying angle of at least one facet) by means of the pathway to computing resources. It should be noted that, if the chosen implementation is most suitable, steps S101 to S105 may be performed simultaneously and / or at least partially sequentially.

[0054] The foregoing has presented embodiments and details thereof as part of the present invention, which can provide one or more advantages by improving the power control mechanism in ophthalmic imaging instruments that allow for flexibility in providing multiple imaging modalities while maintaining safety without increasing the system and / or implementation. While various embodiments of this disclosure have been described above, it should be understood that they are presented by way of example and not limitation. It will be apparent to those skilled in the art that various changes in form and detail can be made. Therefore, the exemplary embodiments described above are not limiting.

[0055] While this specification contains numerous details of specific embodiments, these should not be construed as limiting the scope of any invention or potentially claimed content, but rather as descriptions of features specific to the particular embodiments described herein. Certain features described in this specification within the context of individual embodiments may also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented individually or in any suitable sub-combination in multiple embodiments. Furthermore, although features may be described above as acting in a particular combination and even initially claimed in this way, one or more features from a claimed combination may be removed from the combination in some cases, and the claimed combination may be for a sub-combination or a variation thereof.

Claims

1. An ophthalmic imaging instrument (102, 120), comprising: A light source (200) is arranged to emit a beam (201); A polygonal scanning mirror (202) includes a plurality of reflective facets (2021, 2022, ...), each reflective facet extending in a corresponding first direction (d1) in the plane of rotation of the polygonal scanning mirror (202) and in a common second direction (d2) orthogonal to the plane of rotation of the polygonal scanning mirror (202); A driver (203) is arranged to rotate the polygonal scanning mirror (202) in the plane of rotation during operation such that each facet (2021, 2022, ...) reflects the light beam (201). Optical element (204), which is arranged to guide the light beam (201) reflected from the polygonal scanning mirror (201) toward the subject's eye (E) and to direct the light (L) returning from the eye (E) toward the subject's eye (E). R ) is guided toward the polygonal scanning mirror (202); Detector (205), which is arranged to detect reflected light (L) from the polygonal scanning mirror (202). R ) to generate a detection signal (S) d ); Aperture (206), the aperture being arranged to constrain the return light (L) reaching the detector (205). R ), so that it is light reflected from a region (2021(A)) of each facet (2021, 2022, ...), said region extending at least one of the same first distance on each facet along its respective first direction (d1) and the same second distance on the common second direction (d2) of each facet; and A path (207) to computing resources (106), the computing resources being arranged to use the detection signal (S) d ) Generate an image (210) of the eye (E), the detection signal (S) d The reflected light (L) is reflected from at least one facet (2021, 2022, ...). R )generate.

2. The ophthalmic imaging device (102, 120) according to claim 1, wherein, The region (2021(A)) of each facet (2021, 2022, ...) is a region of the same size, which extends the same first distance along its respective first direction (d1) on each facet and the same second distance along the common second direction (d2) on each facet.

3. The ophthalmic imaging instrument (102, 120) according to claim 2, wherein, During operation, the driver (203) rotates the polygonal scanning mirror (202) in the plane of rotation such that each facet (2021, 2022, ...) reflects the light beam (201) at a varying angle (α), and wherein, only during the rotation of the polygonal scanning mirror (202) corresponding to the same portion (β) of the varying angle (α) for each facet (2021, 2022, ...), the optical element (204) guides the light beam (201) reflected from the polygonal scanning mirror (202) toward the subject's eye (E).

4. The ophthalmic imaging instrument (102, 120) according to any one of claims 1 to 2, wherein, During operation, the driver (203) rotates the polygonal scanning mirror (202) in the plane of rotation such that each facet (2021, 2022, ...) reflects the light beam (201) at a varying angle (α), and wherein the detection signal (S) used to generate the image (210) of the eye (E) is... d The detection signal (S) is generated during the rotation of the polygonal scanning mirror (202) at the corresponding portion (β) of the angle (α) corresponding to the change of the at least one facet (2021, 2022, ...), and is not used to generate the image (210) of the eye (E). d The computational resource (106) is ignored.

5. The ophthalmic imaging instrument (102, 120) according to any one of the preceding claims, wherein, The aperture (206) is also arranged such that the light beam (201) and the return light (L) R The light passes through the aperture (206) to be reflected from each facet (2021, 2022, ...) of the polygonal scanning mirror (202), and the returned light (L) is reflected back through the aperture (206). R The projection is onto the region (2021(A)) of each facet so as to reflect from the region (2021(A)) of each facet.

6. The ophthalmic imaging instrument (102, 120) according to any one of the preceding claims, wherein the plurality of facets (2021, 2022, ...) are rectangular, each facet having a length defined by the lengths of two edges (2021-3, 2021-4) parallel to the plane of rotation and a width defined by the lengths of two edges (2021-1, 2021-2) orthogonal to the plane of rotation, and the aperture (206) is rectangular, having a length defined by the lengths of two edges (206-3, 206-4) parallel to the plane of rotation and a width defined by the lengths of two edges (206-1, 206-2) orthogonal to the plane of rotation.

7. The ophthalmic imaging instrument (102, 120) according to any one of the preceding claims, wherein, The region (2021(A)) of each facet (2021, 2022, ...) is the central region (2021(A)) of the facet surrounded by the outer peripheral region (2021(B)) on the facet.

8. The ophthalmic imaging instrument (102, 120) according to claim 7, wherein, The interval between the central region (2021(A)) and the periphery of each facet is greater than or equal to a predetermined distance (222, 223).

9. The ophthalmic imaging instrument (102, 120) according to claim 8, wherein, The predetermined distance (222, 223) is 0.1%, 1% or 10% of the distance by which the facet extends in at least one of its respective first direction (d1) and the common second direction (d2).

10. The ophthalmic imaging instrument (102, 120) according to any one of the preceding claims, wherein, The polygonal scanning mirror (202) is surrounded by a housing (208) with an opening (209).

11. The ophthalmic imaging instrument (102, 120) according to claim 10, wherein, The opening (209) includes a phase mask (210).

12. The ophthalmic imaging instrument (102, 120) according to claim 10 or claim 11, wherein, The hole (206) is in the plate (207), and the plate (207) is attached to the housing (208) through the opening (209) of the housing (208) so that the hole (206) and the opening (209) are aligned.

13. The ophthalmic imaging instrument (102, 120) according to any one of the preceding claims, wherein, Using the detection signal (S) d ) generates the image (210) of the eye (E), the detection signal (S) d The reflected light (L) is the light reflected by all facets (2021, 2022, ...) during the rotation of the polygonal scanning mirror (202). R Generated by ).

14. The ophthalmic imaging instrument (102, 120) according to any one of the preceding claims, wherein, The polygonal scanning mirror (202) is a regular convex polygon with 16 facets.

15. A method of operating an ophthalmic imaging instrument (102, 120) according to any one of the preceding claims, the method comprising: - The polygonal scanning mirror (202) is rotated (S101) by means of the driver (203) such that each facet (2021, 2022, ...) reflects the light beam (201). -The light beam (201) reflected from the polygonal scanning mirror (202) is guided toward the subject's eye (E) by means of the optical element (204) (S102). -The light (L) returned from the eye (E) is transmitted by means of the optical element (204). R (S103) guides the polygonal scanning mirror (202) toward the polygonal scanning mirror. - By means of the detector (205), the returned light (L) constrained by the aperture (206) is detected. R (S104) Generate the detection signal (S) d );as well as - Using the computing resources (106), the reflected light (L) reflected from at least one facet is utilized. R The detection signal (S) generated by the signal is d (S105) Generate (210) the image of the eye (E).

Images