Systems and methods of optical coherence tomography with a multi-focal delay line

Patent metadata

Field	Value
Publication number	US-2016227997-A1
Application number	US-201514968615-A
Country	US
Kind code	A1
Filing date	Dec 14, 2015
Priority date	Feb 6, 2015
Publication date	Aug 11, 2016
Grant date	—

Abstract

An optical coherence tomography (OCT) system includes: a light source; a multi-focal delay line; and a light detector. The multi-focal delay line includes: a positive lens; and an optical switch configured to: receive a light from the light source; selectively direct the sample light to the positive lens via a selected one of a plurality of light interfaces each located a different distance from the focal plane of the positive lens; and direct the sample light to an object to be measured. The light detector is configured to receive return light returned from the object to be measured in response to the sample light, and to receive a reference light produced from the light from the light source, and in response thereto to detect at least one interference signal. An associated OCT method may be performed with the OCT system.

First claim

We claim:

1 . A system, comprising:
a light source configured to emit light; a first optical system configured to receive the light from the light source and to produce therefrom reference light and sample light; a reference optical path configured to receive the reference light from the first optical element; a multi-focal delay line, comprising:
an optical switch configured to receive the sample light from the first optical system and to selectively couple the sample light to a selected light interface among a plurality of light interfaces, and
a positive lens system, wherein the light interfaces are all separated and spaced apart from the positive lens system and located at different distances than each other from an effective focal plane of the positive lens, wherein the positive lens system is configured to receive the sample light from the selected light interface, to provide the sample light to an eye, to receive return light from the eye, and to provide the return light to the selected light interface,
wherein the optical switch is further configured to provide the return light to the first optical system;
a light detector configured to receive the reference light from the reference optical path, and to receive the return light from the first optical system, and in response thereto to detect at least one interference signal; and one or more processors configured to control the optical switch to selectively couple the sample light to each of the plurality of light interfaces, one at a time, and further configured to measure at least one characteristic of the eye from the detected interference signals when the sample light is selectively coupled to the plurality of light interfaces.

2 . The system of claim 1 , wherein the optical switch has a plurality of output ports, and wherein the multi-focal delay line includes a plurality of optical waveguides each connected to one of the output ports, the plurality of optical waveguides providing the plurality of light interfaces.

3 . The system of claim 2 , wherein each of the light interfaces comprises a second end of a corresponding one of the optical waveguides.

4 . The system of claim 3 , further comprising an integrated optical circuit including the optical switch, an adjustable optical delay, and the optical waveguides.

5 . The system of claim 1 , wherein the optical switch has a plurality of output ports, and wherein the multi-focal delay line comprises a plurality of optical fibers each having a first end coupled to one of the plurality of output ports, and wherein each of the light interfaces comprises a second end of a corresponding one of the optical fibers.

6 . The system of claim 5 , wherein each of the optical fibers has a different length.

7 . The system of claim 1 , wherein the one or more processors are further configured to determine at least one distance between two different components of the eye from the detected interference signals when the sample light is selectively coupled to the light interfaces.

8 . The system of claim 7 , where the distances include at least one of: a distance between a reference plane and the anterior surface of a cornea, a distance between a surface of a cornea and a surface of a lens, a distance between a surface of the lens and a retina; and a distance between a surface of the cornea and the retina.

9 . The system of claim 1 , wherein the optical system includes at least one scanning device configured to scan the sample light on the eye in at least one direction.

10 . The system of claim 1 , wherein at least one of the light interfaces is distanced from the positive lens so that the sample light provided from the optical system to the eye is substantially focused on the retina.

11 . The system of claim 10 , wherein at least another one of the light interfaces is distanced from the positive lens so that the sample light provided from the optical system to the eye is substantially focused on a cornea of the eye.

12 . The system of claim 10 , wherein at least another one of the light interfaces is distanced from the positive lens so that the sample light provided from the optical system to the eye is substantially focused on a lens of the eye.

13 . The system of claim 1 , wherein the light produced by the light source has a coherence length, and wherein the light interfaces are arranged with respect to the focal plane of the positive lens system such that the return light from the eye for a first one of the light interfaces principally comes from a first depth in the eye and the return light from the eye for a second one of the light interfaces principally comes from a second depth in the eye different from the first depth, and wherein a distance between the first depth and the second depth is greater than the coherence length.

14 . The system of claim 13 , wherein the system is further configured to automatically change a delay provided by the multi-focal delay line to match each of the first and second depths when the light is output from the first one of the light interfaces and the second one of the light interfaces, respectively.

15 . The system of claim 1 , wherein the light interfaces are all disposed within three degrees of an optical axis of the positive lens.

16 . The system of claim 1 , wherein the first optical system includes a beam splitter configured to receive the light from the light source and to produce therefrom the reference light and the sample light.

17 . The system of claim 1 , wherein the first optical system includes a fiber optical coupler configured to receive the light from the light source and to produce therefrom the reference light and the sample light.

18 . A method, comprising:
producing sample light and reference light from a common light source; controlling an optical switch to direct the sample light to an eye via a first selected light interface and a positive lens; detecting at least one first interference signal from the reference light and return light returned from the eye in response to the sample light being directed to the eye via the first selected light interface; controlling the optical switch to direct the sample light to the eye via a second selected light interface and the positive lens, wherein the second selected light interface is disposed at a different distance from a focal plane of the positive lens than the first selected light interface; detecting at least one second interference signal from the reference light and return light returned from the eye in response to the sample light being directed to the eye via the second selected light interface; and determining at least one distance between at least two different features of the eye from the detected first and second interference signals.

19 . The method of claim 18 , wherein the first selected light interface is distanced from the positive lens so that the sample light provided to the eye is substantially collimated.

20 . The method of claim 19 , wherein the second selected light interface is distanced from the positive lens so that the sample light is focused on a cornea of the eye.

21 . The method of claim 20 , further comprising determining a distance between the cornea and a retina of the eye from the detected first and second interference signals.

22 . The method of claim 18 , further comprising scanning the sample light in at least one direction so as to create a plurality of first interference signals from the referen

Assignees

• Amo Wavefront Sciences Llc

Inventors

• Pulaski Paul
• Neal Daniel R
• Raymond Thomas D
• Farrer Stephen W
• Hamrick Daniel R
• Copland Richard J

Classifications

• A61B3/0025

  characterised by electronic signal processing, e.g. eye models · CPC title

• G02B6/12004

  Combinations of two or more optical elements · CPC title

• A61B3/102 Primary

  for optical coherence tomography [OCT] · CPC title

• A61B3/1005

  for measuring distances inside the eye, e.g. thickness of the cornea (A61B3/11 takes precedence) · CPC title

• G02B2006/12145

  Switch · CPC title