Ophthalmic imaging with K-mirror scanning, efficient interferometry, and pupil alignment through spatial frequency analysis

Patent metadata

Field	Value
Publication number	US-12539033-B2
Application number	US-202017628107-A
Country	US
Kind code	B2
Filing date	Jul 30, 2020
Priority date	Aug 1, 2019
Publication date	Feb 3, 2026
Grant date	Feb 3, 2026

Abstract

Various techniques for providing a low-cost ophthalmic imaging system, such an OCT or fundus imagers are presented. Cost is reduced by using a K-minor as a scanning component. The K-mirror is positioned at a retina conjugate. A beam splitter is positioned at the pupil conjugate and may be used to provide pupil splitting functionality. The beam splitter's shape and area conform to the focal light footprint of an illumination source such that it spans only a fraction of a collection window. 2D FFT is applied to capture spectra for purposes of selectively removing complex conjugate components and for extracting patient pupil to system collection pupil alignment. Consequently, pupil alignment is achieved by use of captured OCT data without the need for additional pupil cameras.

First claim

The invention claimed is:

1 . An ophthalmic imaging system for imaging a target region of an eye, comprising:
a light source creating an illumination beam; a first optical element receiving the illumination beam and focusing the illumination beam along a non-collimated path; a beam scanning mechanism in the non-collimated path and positioned at a conjugate plane of the target region, the beam scanning mechanism having an entrance receiving the illumination beam from the first optical element, and having an exit outputting a scan beam whose scanning position is dependent upon motion of the scanning mechanism; and a second optical element receiving the scan beam from the beam scanning mechanism, the second optical element focusing the scan beam onto the target region of the eye.

2 . The system of claim 1 , wherein the target region is the retina of the eye, and the beam scanning mechanism is positioned at a retina conjugate of the eye.

3 . The system of claim 1 , wherein the beam scanning mechanism includes a K-mirror.

4 . The system of claim 1 , wherein the beam scanning mechanism receives the illumination beam along the direction of the optical axis, and outputs the scan beam along the same direction of the optical axis.

5 . The system of claim 1 , wherein:
the first optical element is a scan lens, the second optical element is an ocular lens, and the scan lens focusses the illumination beam to a focal point within the beam scanning mechanism.

6 . The system of claim 1 , wherein the illumination beam is a line beam that traverses an axial output direction of the light source.

7 . The system of claim 1 , wherein the beam scanning mechanism is rotatable to define a two-dimensional illumination pattern comprised of the scan beam rotated by the rotation of the beam scanning mechanism.

8 . The system of claim 1 , wherein the beam scanning mechanism includes a plurality of reflective surfaces including an output-facing reflective surface at the exit that outputs the scan beam, the output-facing reflective surface being configurable to be radially displaced and impart a corresponding radial displacement to the scan beam.

9 . The system of claim 8 , wherein the output-facing reflective surface is at a predefined angle to the exit axis of the scanning mechanism, and wherein the output-facing reflective surface is radially displaced along the predefined angle, the illumination beam is a line beam having a first length, and the scan beam is radially displaced by at least the length of the line beam.

10 . The system of claim 9 , wherein the illumination pattern has an annular shape.

11 . The system of claim 1 , wherein the beam scanning mechanism rotates about the axis of the output scan beam, and the output scan beam rotates a multiple of times for each rotation of the beam scanning mechanism, the multiple of times excluding a multiple of one.

12 . The system of claim 1 , wherein the ophthalmic imaging system is an optical coherence tomography system (OCT), optical coherence tomography angiography system (OCTA), or fundus imaging system.

13 . The system of claim 1 , wherein the light source is a linear series of light emitting diodes (LEDs), each selectively actuatable.

14 . The system of claim 1 , wherein the light source is a circular arrangement of light emitting diodes (LEDs) actuatable in a predefined pattern.

15 . The system of claim 1 , wherein the beam scanning mechanism includes at least one frequency-selective optic that is reflective to a first beam frequency and transmissive to a second beam frequency, the beam scanning mechanism defining a second light path directing light of the second beam frequency to the exit.

16 . The system of claim 15 , wherein the illumination beam at the entrance to the beam scanning mechanism includes a first light component of said first beam frequency and a second light component of said second beam frequency, the output scan beam is defined by the first light component, and the second light component defines a fixation image along the second light path to the exit.

17 . The system of claim 1 , wherein the beam scanning mechanism includes at least one mirror that has a first surface reflective to the illumination beam received at the entrance and a second surface that is transmissive to a second illumination beam, the second surface being opposite the first surface and forming a second entrance to the beam scanning mechanism.

18 . The system of claim 1 , further comprising a motion translation mechanism coupled to the beam scanning mechanism and imparting one-dimensional translational motion to the beam scanning mechanism.

19 . The system of claim 18 , wherein the motion translation mechanism includes a parallel flexture.

20 . The system of claim 19 , wherein the motion translation mechanism includes an inductive actuator or motor with excenter.

21 . The system of claim 1 , further comprising a scanning system including a first scanning component that produces a first scanning signal input to a second scanning component that includes said beam scanning mechanism;
wherein the first scanning component is positioned at a pupil conjugate of the eye, and second scanning component is positioned at a retina conjugate of the eye.

22 . The system of claim 21 , wherein the first scanning component includes galvanometer positioned at the pupil conjugate and the beam scanning mechanism is positioned at the retina conjugate.

Assignees

• Zeiss Carl Meditec Inc
• Zeiss Carl Meditec Ag

Inventors

• Wang Yingjian
• Liu Yuan
• Straub Jochen
• Darvishzadeh Varcheie Mahsa
• Leahy Conor

Classifications

• G02B26/105

  with one or more pivoting mirrors or galvano-mirrors (G02B26/101 takes precedence) · CPC title

• A61B5/7257

  using Fourier transforms · CPC title

• A61B3/152

  for aligning · CPC title

• A61B3/14

  Arrangements specially adapted for eye photography · CPC title

• A61B3/1233

  for measuring blood flow, e.g. at the retina · CPC title