CN116687322A - Variable-focus OCT capsule endoscopic oral cavity imaging device and working method thereof - Google Patents

Abstract

The application relates to a variable focus OCT capsule endoscopic oral imaging device and a working method thereof, the device comprises an optical fiber sleeve, a single-mode optical fiber, a hollow annular rotating motor, a collimating lens, an achromatic lens, a beam expanding lens, an all-solid-state variable focus element based on piezoelectric driving, a reflecting mirror and a capsule type shell, wherein OCT excitation light enters the OCT capsule endoscopic oral imaging device through the single-mode optical fiber, and after being collimated by the collimating lens, the OCT excitation light sequentially passes through the achromatic lens, the beam expanding mirror, the all-solid-state variable focus element based on piezoelectric driving and the reflecting mirror and focuses a light beam on a sample, OCT signals from the sample return to the collimating lens through the same light path, and OCT signals are output through the single-mode optical fiber for image reconstruction. The application realizes the dynamic adjustment of OCT excitation light beams through the all-solid-state variable-focus element, and avoids the defocusing of light spots caused by irregular and uneven imaging tissue surfaces.

Description

Variable-focus OCT capsule endoscopic oral cavity imaging device and working method thereof

Technical Field

The application relates to the technical field of medical equipment, in particular to a variable-focus OCT capsule endoscopic oral imaging device and a working method thereof.

Background

Oral cancer is one of common malignant diseases, and because the incidence is hidden, early symptoms are not obvious, patients are usually diagnosed with middle and late stages when the patients visit the doctor, and the cure rate of the middle and late stage patients is low generally, and the prognosis is poor; therefore, achieving early detection and early treatment of patients with oral cancer is of great significance in improving survival rate of patients.

The current oral cancer examination method mainly depends on tissue pathology biopsy, however, on one hand, the biopsy is easy to cause false negative due to the problem of sample size; on the other hand, biopsy is an invasive procedure, so that a noninvasive, omnibearing and high-resolution oral cancer screening method needs to be developed, so that early detection and treatment of oral cancers are realized.

Compared with the traditional optical imaging technology, the OCT imaging technology can obtain micron-level resolution at millimeter-level imaging depth, and based on the basic principle of weak coherent light interference, in the OCT imaging process, when near infrared weak coherent light irradiates an imaging area, tissue signal light of a sample arm interferes with reference light of a reference arm, high-resolution three-dimensional morphological structure information of biological tissues can be obtained through scanning, however, most of current OCT-based imaging devices have fixed excitation beam focal length, and the light spot focusing degree cannot be adjusted in real time according to the morphological change of a sample, which generally causes defocusing and image distortion of a light beam focusing focus.

The Chinese patent application number is 201720133946.4, and the patent name is a high-resolution OCT capsule endoscope, which discloses a high-resolution OCT capsule endoscope, and the endoscope has a simple structure, and improves the transverse and axial resolutions of endoscopic imaging by arranging an achromatic/beam-expanding lens group, however, the endoscopic device cannot adjust the focusing depth of an excitation beam in real time, and cannot avoid image distortion caused by irregular shape of a sample.

The application discloses a self-focusing OCT endoscope with a variable working distance, which has the patent name of 'self-focusing OCT endoscope with a variable working distance' with 202010020276.1, and uses near infrared laser signals emitted and received by OCT as the basis for adjusting the working distance of the endoscope to realize self-focusing OCT imaging with the variable working distance; however, the focusing element adopted by the method is a liquid lens, the element is easy to leak liquid and is influenced by gravity, electromagnetic interference can be generated when the focusing element is driven by magnetism, the response speed is low, the volume is large, the driving voltage is too high, and in addition, when the endoscopic probe performs annular scanning, the internal element layout can interfere with the scanning area of the light beam, so that the imaging quality is influenced.

Disclosure of Invention

In view of the above-mentioned shortcomings of the prior art, the present application aims to provide a variable focus OCT capsule endoscopic oral cavity imaging device, by which real-time focusing of excitation light beams in the OCT endoscopic imaging process can be realized, and problems such as image distortion caused by light spot defocusing due to irregular and uneven oral tissue surfaces can be avoided.

In order to achieve the above object, the present application provides a variable focus OCT capsule endoscopic oral imaging device, which is characterized in that: the optical element combination sequentially comprises a single-mode optical fiber, a collimating lens, an achromatic lens, a beam expanding lens, an all-solid-state variable focusing element based on piezoelectric driving and a reflecting mirror which are arranged on the same optical axis along the propagation direction of an optical path, wherein OCT excitation light input by the single-mode optical fiber is collimated by the collimating lens to form first collimated light, the first collimated light is expanded to form second collimated light after passing through the achromatic lens and the beam expanding lens, and the second collimated light is focused on a sample outside the capsule shell by the reflecting mirror after being focused by the all-solid-state variable focusing element based on piezoelectric driving;

the piezoelectric driving-based all-solid-state variable focus element is electrically connected with a second cable extending from the outside of the capsule type shell, and the curvature radius of the surface of the piezoelectric driving-based all-solid-state variable focus element is changed by the power supply driving of the second cable so as to change the focusing depth of OCT excitation light.

Further, the all-solid-state variable focus element based on piezoelectric driving consists of piezoelectric ceramics, a glass film, a polydimethylsiloxane elastic polymer and a glass substrate; the piezoelectric driving-based all-solid-state variable focus element is powered by a second cable to drive piezoelectric ceramics to deform a glass film and a polydimethylsiloxane elastic polymer, so that the curvature radius of the surface of the element is changed to change the focusing depth of OCT excitation light.

Further, the capsule type shell comprises an inner shell and an outer shell which are made of transparent materials, and the inner shell and the outer shell can rotate relatively.

Further, the collimating lens, the achromatic lens, the beam expander lens, and the piezo-electric driving-based all-solid-state variable focus element are sequentially fixed in an optical element mounting frame disposed at the axial center of the inner cavity of the capsule type housing, and the optical element mounting frame is fixed on the inner housing.

Furthermore, a circular hole is arranged in the center of the top of the inner shell of the capsule type shell, a tubular reflector fixing base with a hollow bottom is fixed in the inner shell with the same axis of the circular hole, and the reflector is fixed on the reflector fixing base.

Further, a cylindrical stator is fixed at the center of the top of the capsule shell; the oral area of capsule type casing is equipped with cavity annular rotating electrical machines in, and single mode optical fiber passes from the central passageway of cavity annular rotating electrical machines, cavity annular rotating electrical machines's pivot part links to each other with the inner shell proximal end portion of capsule type casing, cavity annular rotating electrical machines's fixed part links to each other with the shell proximal end portion of capsule type casing, and the fixed stator in shell distal end top center of capsule type casing inserts the hole in the inner shell distal end top center.

Further, the hollow annular rotating motor is electrically connected with a first cable, the first cable supplies electricity to the hollow annular rotating motor, and the hollow annular rotating motor drives the capsule type shell inner shell and the optical element to rotate in a combined mode after electricity is supplied to the hollow annular rotating motor, so that annular scanning is achieved.

Further, when the single-mode fiber does not enter the capsule cavity, the single-mode fiber is wrapped by the optical fiber sleeve, and the part of the single-mode fiber entering the capsule shell cavity is fixed along the central axis of the capsule shell.

Further, the proximal end portion of the capsule housing is streamlined, the distal end portion is hemispherical, and the middle section portion is cylindrical.

The application discloses a working method of a variable focus OCT capsule endoscopic oral imaging device, which comprises the following steps:

the first step: the OCT excitation light source inputs incident light through a single-mode fiber, the incident light sequentially passes through a collimating lens, an achromatic lens, a beam expanding lens and an all-solid-state variable-focus element based on piezoelectric driving and then is reflected to the surface of a sample through a reflecting mirror, and in the process, the focusing depth of the excitation light beam is changed by adjusting the all-solid-state variable-focus element based on the piezoelectric driving according to the imaging effect, so that light spots caused by unevenness and irregularity of the sample are avoided.

And a second step of: the hollow annular rotating motor drives the inner shell of the capsule type shell to carry out 360-degree annular scanning, the back scattering light signals generated by the obtained focusing light spots inducing tissues on the sample return through the same light path, the back scattering light signals are detected by the detector after being interfered by signal light of the single-mode fiber output and the reference arm, and OCT images of biological samples are obtained after computer image processing.

Compared with the prior art, the application has the following advantages:

1. the application realizes the real-time focusing of the excitation light beam in the OCT endoscopic imaging process and avoids the problems of image distortion and the like caused by defocusing of light spots due to irregular and uneven oral mucosa tissue surfaces.

2. Compared with the traditional liquid lens, the application has the advantages of simple structure, small volume, low power consumption, no electromagnetic interference and the like, can not be influenced by gravity, and has more accurate focusing effect.

3. The application adopts the hollow annular rotating motor to realize annular scanning of the endoscopic probe, and the designed novel internal element layout avoids the influence of an internal cable on scanning imaging, thereby further improving the imaging quality.

Drawings

FIG. 1 is a schematic diagram of a variable focus OCT capsule endoscopic oral imaging device;

FIG. 2 is a schematic diagram of an all-solid-state variable focus element based on piezoelectric actuation;

wherein: 1. a single mode optical fiber; 2. a hollow annular rotary electric machine; 3. an optical fiber ferrule; 4. a capsule type housing; 5. a collimating lens; 6. an achromatic lens; 7. a beam expanding lens; 8. an all-solid-state variable focus element based on piezoelectric actuation; 9. a reflecting mirror; 10. a mirror fixing base; 11. a stator; 12. a first cable; 13. a second cable; 14. piezoelectric ceramics; 15. a glass film; 16. a polydimethylsiloxane elastomeric polymer; 17. a glass substrate.

Detailed Description

In order that those skilled in the art will better understand the present application, a technical solution in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in which it is apparent that the described embodiments are only some embodiments of the present application, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.

The embodiment discloses a variable focus OCT capsule endoscopic oral imaging device, the whole structure schematic diagram of which is shown in fig. 1, comprising a capsule type shell 4, a hollow annular rotating motor 2, and an optical element combination for OCT imaging, wherein: along the propagation direction of the optical path, the optical element combination for OCT imaging sequentially comprises a single-mode optical fiber 1, a collimating lens 5, an achromatic lens 6, a beam expanding lens 7, an all-solid-state variable focus element 8 based on piezoelectric driving and a reflecting mirror 9 which are coaxially arranged; the OCT excitation light input by the single-mode fiber 1 enters an OCT capsule endoscopic imaging device in operation and is collimated by the collimating lens 5 to form first collimated light, the first collimated light is expanded by the achromatic lens 6 and the beam expanding lens 7 to form second collimated light, and the second collimated light is focused on a sample outside the capsule shell 4 by the reflecting mirror 9 after being focused by the all-solid-state variable-focus element 8 based on piezoelectric driving.

The piezoelectric driving-based all-solid-state variable focus element 8 is electrically connected with a second cable 13 extending from the outside of the capsule type casing, and the second cable 13 is used for supplying power to drive to change the curvature radius of the surface of the piezoelectric driving-based all-solid-state variable focus element so as to change the focusing depth of OCT excitation light.

Specifically, the collimating lens 5, the achromatic lens 6, the beam expanding lens 7 and the all-solid-state variable focus element 8 based on piezoelectric driving are sequentially fixed in an optical element mounting frame arranged at the axial center of the inner cavity of the capsule shell 4, and the mounting frame is formed by 3D printing according to the shape of each optical element; the all-solid-state variable focus element 8 based on piezoelectric driving consists of piezoelectric ceramics 14, a glass film 15, a polydimethylsiloxane elastic polymer 16 and a glass substrate 17; the element is powered by a second cable 13 and drives a piezoelectric ceramic 14 to deform a glass film 15 and a polydimethylsiloxane elastic polymer 16, so that the curvature radius of the surface of the element is changed to change the focusing depth of the OCT excitation beam.

The collimator lens 5 is a conventional optical component for aligning the light beam in a specific direction to form a collimated light ray or a parallel light ray.

The achromatic lens 6 is an existing optical component, and can correct only positional chromatic aberration (red, blue two colors) and spherical aberration (yellow-green light) of points on the axis and eliminate near-axis point coma, cannot correct chromatic aberration and spherical aberration of other chromatic light, and has a large field curvature.

The beam expander lens 7 is an existing optical component that is a lens assembly capable of changing the laser beam diameter and divergence angle.

The all-solid-state variable focus element 8 based on piezoelectric driving can also be specifically an all-solid-state variable focus electrostatic driving type micro lens based on PDMS film, which is disclosed in Chinese patent application No. 202010027467.0.

The capsule type shell 4 is divided into an inner shell and an outer shell, both are made of transparent materials, and the inner shell and the outer shell can rotate relatively so as to be used for OCT scanning imaging, and the relative rotation of the inner shell and the outer shell can be realized manually or fixed through the outer shell, and the inner shell is driven to rotate through a motor.

Specifically, a circular hole is formed in the center of the top of the inner shell of the capsule shell 4, a hollow reflector fixing base 10 is fixed in the inner shell with the same axis of the hole, the reflector fixing base 10 is tubular, the reflector 9 is fixed on the inner end of the reflector fixing base 10, and a cylindrical stator 11 is fixed in the center of the top of the outer shell of the capsule shell 4.

In order to realize the relative rotation of the inner shell and the outer shell under the action of a motor, a hollow annular rotating motor 2 is arranged in the opening part of the capsule-shaped shell, a single-mode optical fiber 1 passes through a central channel of the hollow annular rotating motor 2, a rotating shaft part of the hollow annular rotating motor is connected with the near end part of the inner shell 401 of the capsule-shaped shell, a fixed part of the hollow annular rotating motor is connected with the near end part of the outer shell 402 of the capsule-shaped shell, a stator fixed at the center of the far end top of the outer shell of the capsule-shaped shell is inserted into a hole at the center of the far end top of the inner shell, the hollow annular rotating motor is electrically connected with a first cable, the first cable 12 is used for powering the hollow annular rotating motor 2, and the hollow annular rotating motor is powered to drive the inner shell of the capsule-shaped shell and an optical element to rotate in a combined way so as to realize annular scanning.

When the single-mode optical fiber 1 does not enter the capsule cavity, the single-mode optical fiber is wrapped by the optical fiber sleeve 3, and the optical fiber sleeve 3 can be connected with the inner shell after passing through the hollow annular rotating motor 2.

The part of the single-mode fiber 1 entering the capsule cavity is fixed along the central axis of the capsule shell 4; the capsule housing 4 has a streamlined front end portion, a hemispherical rear end portion, and a cylindrical middle portion.

The embodiment relates to a panoramic scanning method of the device, which comprises the following steps:

the first step: the OCT excitation light source inputs incident light through the single-mode optical fiber 1, the incident light sequentially passes through the collimating lens 5, the achromatic lens 6, the beam expanding lens 7 and the all-solid-state variable-focus element 8 based on piezoelectric driving and then is reflected to the surface of a sample through the reflecting mirror 9, and in the process, the focusing depth of the excitation light beam can be changed by adjusting the all-solid-state variable-focus element 8 based on the piezoelectric driving according to the imaging effect, so that the light spot defocusing caused by the unevenness and the irregularity of the sample is avoided.

And a second step of: the hollow annular rotating motor 2 drives the inner shell part of the capsule type shell 4 to carry out 360-degree annular scanning, the back scattering light signal generated by the induction of the tissue on the sample by the obtained focusing light spot returns through the same light path, the back scattering light signal is detected by the detector after being interfered by the signal light of the reference arm through the single-mode fiber 1, and the OCT image of the biological sample is obtained after the OCT image is processed by the computer image.

The above examples are preferred embodiments of the present application, but the embodiments of the present application are not limited to the above examples, and any other changes, modifications, substitutions, combinations, and simplifications that do not depart from the spirit and principle of the present application should be made in the equivalent manner, and the embodiments are included in the protection scope of the present application.

Claims (10)

1. The utility model provides a variable focus OCT capsule endoscopic oral cavity image device which characterized in that: the optical element combination sequentially comprises a single-mode optical fiber, a collimating lens, an achromatic lens, a beam expanding lens, an all-solid-state variable focusing element based on piezoelectric driving and a reflecting mirror which are arranged on the same optical axis along the propagation direction of an optical path, wherein OCT excitation light input by the single-mode optical fiber is collimated by the collimating lens to form first collimated light, the first collimated light is expanded to form second collimated light after passing through the achromatic lens and the beam expanding lens, and the second collimated light is focused on a sample outside the capsule shell by the reflecting mirror after being focused by the all-solid-state variable focusing element based on piezoelectric driving;

the piezoelectric driving-based all-solid-state variable focus element is electrically connected with a second cable extending from the outside of the capsule type shell, and the curvature radius of the surface of the piezoelectric driving-based all-solid-state variable focus element is changed by the power supply driving of the second cable so as to change the focusing depth of OCT excitation light.

2. The variable focus OCT capsule endoscopic oral imaging device of claim 1, wherein the piezo-electric drive based all-solid state variable focus element is composed of a piezo-ceramic, a glass film, a polydimethylsiloxane elastomeric polymer, and a glass substrate; the piezoelectric driving-based all-solid-state variable focus element is powered by a second cable to drive piezoelectric ceramics to deform a glass film and a polydimethylsiloxane elastic polymer, so that the curvature radius of the surface of the element is changed to change the focusing depth of OCT excitation light.

3. The variable focus OCT capsule endoscopic oral imaging device of claim 2, wherein the capsule housing comprises an inner housing and an outer housing, both made of transparent materials, the inner housing and the outer housing being rotatable relative to each other.

4. A variable focus OCT capsule endoscopic oral imaging device according to claim 3, wherein the collimating lens, the acromatic lens, the beam expander lens, and the piezo-electric drive based all-solid-state variable focus element are sequentially fixed in an optical element mount disposed in the axial center of the capsule housing, the optical element mount being fixed to the inner housing.

5. The variable focus OCT capsule endoscopic oral imaging device of claim 4, wherein a circular hole is formed in a center of a top portion of the inner housing of the capsule type housing, a tubular mirror fixing base having a hollow bottom is fixed inside the inner housing having the same axis as the circular hole, and the mirror is fixed on the mirror fixing base.

6. The variable focus OCT capsule endoscopic oral imaging device of claim 5, wherein a cylindrical stator is fixed at the center of the top of the capsule housing; the oral area of capsule type casing is equipped with cavity annular rotating electrical machines in, and single mode optical fiber passes from the central passageway of cavity annular rotating electrical machines, cavity annular rotating electrical machines's pivot part links to each other with the inner shell proximal end portion of capsule type casing, cavity annular rotating electrical machines's fixed part links to each other with the shell proximal end portion of capsule type casing, and the fixed stator in shell distal end top center of capsule type casing inserts the hole in the inner shell distal end top center.

7. The variable focus OCT capsule endoscopic oral cavity imaging apparatus of claim 6, wherein the hollow annular rotating motor is electrically connected to a first cable, the first cable powers the hollow annular rotating motor, and the hollow annular rotating motor powers the capsule-shaped housing inner housing and the optical element assembly to rotate after power is applied to the hollow annular rotating motor, thereby realizing annular scanning.

8. The variable focus OCT capsule endoscopic oral imaging device of claim 1, wherein the single mode fiber is wrapped by a fiber optic sleeve when not entering the capsule lumen, the single mode fiber entering the capsule housing lumen portion being fixed along the central axis of the capsule housing.

9. The variable focus OCT capsule endoscopic oral imaging device of claim 1, wherein the capsule housing has a streamlined proximal portion, a hemispherical distal portion, and a cylindrical middle portion.

10. A method of operating a device according to any one of claims 1-9, comprising the steps of:

the first step: the OCT excitation light source inputs incident light through a single-mode fiber, the incident light sequentially passes through a collimating lens, an achromatic lens, a beam expanding lens and an all-solid-state variable-focus element based on piezoelectric driving and then is reflected to the surface of a sample through a reflecting mirror, and in the process, the focusing depth of the excitation light beam is changed by adjusting the all-solid-state variable-focus element based on the piezoelectric driving according to the imaging effect, so that light spots caused by unevenness and irregularity of the sample are avoided from being defocused;

and a second step of: the hollow annular rotating motor drives the inner shell of the capsule type shell to carry out 360-degree annular scanning, the back scattering light signals generated by the obtained focusing light spots inducing tissues on the sample return through the same light path, the back scattering light signals are detected by the detector after being interfered by signal light of the single-mode fiber output and the reference arm, and OCT images of biological samples are obtained after computer image processing.