Mask for polygon scanning mirror in ophthalmic imaging device

Abstract

It is necessary to suppress or eliminate image artifacts formed by back-reflections of the scanning beam while maintaining the system complexity at an acceptable level. [Solution] An ophthalmic imaging device comprising: a light source that emits a light beam; a polygon scanning mirror having multiple reflective facets; a driver configured to rotate the polygon scanning mirror during operation so that each facet reflects the light beam; an optical system that guides the light beam reflected from the polygon scanning mirror through the cornea to the fundus of the eye and guides the reflected light from the fundus to the polygon scanning mirror; a mask that prevents a portion of the light beam reflected from the cornea and at least one of the optical elements of the optical system from reaching the detector; a detector that detects the reflected light and generates a detection signal; and access to a computing resource configured to generate an image of the fundus of the eye using the detection signal.

Claims

1. A light source (200) configured to emit a light beam (201), A polygon scanning mirror (202) having multiple reflective facets (2021, 2022, ...), A driver (203) is configured to rotate the polygon scanning mirror (202) during operation, so that each facet reflects the light beam (201), The light beam (201) reflected from the polygon scanning mirror (202) is guided through the cornea (C) of the subject's eye (E) to the fundus (F) of the eye (E), and the reflected light (L) from the fundus (F) is directed to the fundus (F). Ｒ An optical system (220) configured to guide the ) to the polygon scanning mirror (202), Of the light beam (201) reflected from the polygon scanning mirror (202), a portion of the light beam (201) that is back-reflected from at least one of the cornea (C) of the eye (E) and the optical elements (204, 206, 208) of the optical system (220) (P ２０１ A mask (206) configured to prevent the ) from reaching the detector (205), The reflected light (L) from the polygon scanning mirror (202) Ｒ ) detects the detection signal (S ｄ A detector (205) configured to generate ), The detection signal (S ｄ Access (207) to a computing resource (106) configured to generate an image (210) of the fundus (F) of the eye (E) using ), An ophthalmic imaging device (102, 120) equipped with the following.

2. The reflected light (L) detected during the rotation of the polygon scanning mirror (202) Ｒ Under the circumstances that the above image (210) is formed, the part of the light beam (201) (P ２０１ The ophthalmic imaging apparatus (102, 120) according to claim 1, wherein the mask (206) prevents the light beam (201) from entering a portion of at least one facet of the polygon scanning mirror (202) that is not currently reflecting it.

3. During rotation of the polygon scanning mirror (202), the return light (L Ｒ ) forms the image (210). In this situation, the mask (206) prevents a part (P ２０１ ) of the light beam (201) from entering a part of the first facets (2022, 2023) of the polygon scanning mirror (202) that next reflects or last reflected the light beam (201). The ophthalmic imaging device (102, 120) according to claim 2.

4. The reflected light (L) detected during the rotation of the polygon scanning mirror (202) Ｒ Under the circumstances that the above image (210) is formed, the part of the light beam (201) (P ２０１ A portion of the light beam (201) (P) that can be incident on the first facet (2022, 2023) ２０１ The ophthalmic imaging device (102, 120) according to claim 3, wherein the mask (206) prevents all optical paths of the first facets (2022, 2023) from being incident on them.

5. The ophthalmic imaging apparatus (102, 120) according to claim 3 or 4, wherein the first facet (2022) of the polygon scanning mirror (202) shares an edge (E) with the effective facet (2021) that is currently reflecting the light beam (201), and an obtuse angle (θ) is formed between the light beam (201) and the line from the edge (E) to the point of incidence of the light beam (201) on the effective facet (2021).

6. The ophthalmic imaging apparatus (102, 120) according to any one of claims 1 to 5, wherein the polygon scanning mirror (202) is housed in a housing (208) having an opening (209), the opening (209) extending across a plane (211).

7. The ophthalmic imaging device (102, 120) according to claim 6, wherein the opening (209) is provided with a phase mask (210).

8. The ophthalmic imaging apparatus (102, 120) according to claim 6 or 7, wherein the mask (206) is fixed inside the housing (208).

9. When the effective facet (2021) is parallel to the plane (211), the mask (206) closes the opening (209) of the housing (208) up to the edge (E), thereby blocking the portion (P) of the light beam (201). ２０１ An ophthalmic imaging device (102, 120) according to any one of claims 6 to 8, referencing claim 5, wherein the mask (206) prevents the light from entering the first facet (2022).

10. Each of the plurality of facets (2021, 2022, ...) extends by a first distance in a direction perpendicular to the rotation plane of the polygon scanning mirror (202), and the mask (206) extends by a second distance equal to or greater than the first distance in a direction perpendicular to the rotation plane of the polygon scanning mirror (202), according to any one of claims 1 to 9 (102, 120).

11. The surface (212) of the mask (206) is part of the light beam (201) (P ２０１ An ophthalmic imaging apparatus (102, 120) according to any one of claims 1 to 10, wherein the ) is blocked and, at a predetermined angular rotation position of the polygon scanning mirror (202), each facet of the polygon scanning mirror (202) is parallel to the surface (212) of the mask (206).

12. The image (210) of the fundus (F) of the eye (E) is obtained by the reflected light (L) reflected by all facets (2021, 2022, ...) during the rotation of the polygon scanning mirror (202). Ｒ The detection signal (S) generated from ) ｄ An ophthalmic imaging device (102, 120) according to any one of claims 1 to 11, which is generated using ).

13. The ophthalmic imaging device (102, 120) according to any one of claims 1 to 12, wherein the polygon scanning mirror (202) is a convex polygon having 16 facets.

14. An ophthalmic imaging device according to any one of claims 1 to 13, which is a scanning laser ophthalmoscope (102, 120).

15. A method for operating an ophthalmic imaging device (102, 120) according to any one of claims 1 to 14, The driver (203) rotates the polygon scanning mirror (202) so that each facet (2021, 2022, ...) reflects the light beam (201) (S101), The optical system (220) guides the light beam (201) reflected from the polygon scanning mirror (202) to the fundus (F) of the subject's eye (E) (S102), The optical system (220) reflects the light (L) back from the eye (E). Ｒ ) to be guided to the polygon scanning mirror (202) (S103), The mask (206) allows a portion of the light beam (201) reflected from the polygon scanning mirror (202) to be filtered (P ２０１ ) so that a portion of the light beam (201) (P ２０１ ) blocking (S104), The detector (205) detects the reflected light (L Ｒ The detection signal (S ｄ ) to generate (S105), The computing resource (106) detects the detection signal (S ｄ (S106) to generate the image (210) of the fundus (F) of the eye (E) using, A method that includes this.

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