CN110742574B - OCT confocal and common-path dual-mode endoscopic probe and imaging method - Google Patents

The invention discloses an OCT confocal common-path dual-mode endoscopic probe and an imaging method, wherein a common-path light splitting module separates a confocal light path from an OCT light path, the confocal light path is changed by the confocal light path module and then overlapped with the OCT light path by the common-path light splitting module, and common-path output is realized by sharing a part of optical lenses, so that the requirement on the lens size is reduced, and the probe is miniaturized without correcting a moving image; the common-path structure is adopted, so that the endoscopic probe is small in size and simple to process, and the probe is convenient to share with the existing endoscope imaging channel, so that multi-mode imaging is realized; based on confocal imaging and OCT imaging characteristics, a common-path scanning probe is designed, and the structural characteristics of the common-path scanning probe are not easy to interfere in the same environment, so that the system stability is remarkably enhanced, real-time imaging can be realized, and a correction algorithm is not needed; the technical scheme is not only suitable for biological tissue detection imaging and optical-mechanical-electrical system measurement in industry, but also suitable for object imaging of other micro structures.

OCT confocal and common-path dual-mode endoscopic probe and imaging method

Technical Field

The invention relates to an endoscope, in particular to an OCT confocal and common-path dual-mode endoscopic probe and an imaging method.

Background

In the field of endoscopic medical diagnosis, since a lesion site often occurs on a shallow surface of a tissue, a doctor is required to observe not only imaging of a biological tissue surface but also a structure and a morphology inside the tissue, from which a micro lesion is found. For the existing tomography technologies, such as ultrasound imaging, the resolution is lower while having a deeper imaging depth, and the requirement of finding tiny lesions is not satisfied.

At present, the confocal system has the advantages of clear imaging, continuous slice scanning and image recombination, multi-marking technology, living body observation, acquisition of quantitative information and the like, has high imaging contrast and resolution, and is widely applied to various fields of medicine. On the basis, an optical fiber confocal endoscopic microscope system is rapidly developed. The optical fiber generates a flexible connection form between the objective lens of the confocal microscope and the rest system, so that the system probe can enter the tissue to realize living confocal imaging. Confocal microprobe imaging instruments (CellVizio 100 Series) developed by the Mkt company in France are the best-popularized confocal endoscopic equipment at present, and the confocal microprobe imaging instruments adopt an ultrafine image transmission optical fiber as a probe, enter a human body through an endoscope working channel in a sub-scope mode, and are abutted to tissues to be detected for microscopic imaging.

The endoscopic OCT (Endoscopic optical coherence tomography ) technology is an OCT branch technology that has been born and developed vigorously along with the development of OCT technology in recent decades, and has a core objective of miniaturizing OCT optical imaging devices without reducing resolution, and providing high-resolution OCT images of the lumen of internal organs of a human body. The technology greatly expands the application field of OCT technology, so that an OCT examination object is developed from a body surface organ or a biopsy sample to human viscera, such as blood vessels, digestive tracts, respiratory tracts and the like, and various digestive tract lumens, large digestive tract lumens (such as esophagus and rectum), small digestive tract lumens (such as biliary tract) and the like are related at present. In clinical terms, OCT endoscopy has been used primarily for the examination of atherosclerosis, for the examination of stent placement, and the like. The OCT microprobe is used as a key component in an endoscopic OCT system, can be combined with the prior clinical endoscope or minimally invasive technology, stretches into internal organs of a human body, and collects back scattering signals from biological tissues; meanwhile, the characteristics of small physical size, high mechanical strength and the like are also satisfied.

The two imaging modes are used independently and have the defects that: OCT cannot provide images of cell-level fineness, and accurate stage diagnosis cannot be made simply by relying on OCT; the confocal lens cannot provide depth information, cannot identify the depth of a lesion, and cannot observe the change of tissue level. In particular, in the case of cancer diagnosis, cell morphology can be identified using confocal to identify specific cancer stages, and cancer cell infiltration depth can be identified using OCT to determine the surgical protocol. Thus, OCT, confocal dual-mode endoscopy is now one direction of development. Because the requirements of confocal and OCT on the optical performance of the lenses are different, the current dual-mode endoscope only simply concentrates one OCT lens and one confocal lens in the same endoscope, which can bring about larger probe size and deformation when the OCT image and the confocal image are overlapped due to errors caused by probe movement during image fusion.

Accordingly, the prior art is still in need of improvement and development.

Disclosure of Invention

The invention aims to provide an OCT confocal and common-path dual-mode endoscope probe and an imaging method, and aims to solve the problems that the size of the existing dual-mode endoscope probe is large, and the OCT image and the confocal image are deformed when the probe is overlapped due to errors caused by movement of the probe.

The technical scheme of the invention is as follows: an OCT confocal, common-path, dual-mode endoscopic probe, comprising:

the optical fiber module is used for connecting the optical path to realize the bidirectional transmission of light;

the beam shaping module expands and shapes the OCT light and the confocal light projected from the optical fiber module;

a common-path light-splitting module which selectively transmits or reflects OCT light and confocal light by using a dichroic film, wherein the module is also a part of optical paths of the OCT light and the confocal light;

a confocal optical path module, in which only the confocal light is transmitted, so that the confocal light obtains completely different focal length, aberration and numerical aperture characteristics from the OCT light;

the optical fiber module, the beam shaping module, the common-path light splitting module and the confocal light path module are all arranged in the probe shell.

The OCT confocal common-path dual-mode endoscopic probe comprises an optical fiber module, a beam shaping module, a common-path light splitting module and a confocal light path module, wherein the optical fiber module comprises an optical fiber assembly, and the common-path light splitting module comprises a second lens; the front upper end and the front lower end of the first lens are plated with first reflecting films, the front middle part of the first lens is plated with an antireflection film, the antireflection film is positioned between the first reflecting film at the upper end and the first reflecting film at the lower end, the beam shaping module adopts the part of the first lens plated with the antireflection film, and the confocal optical path module adopts the part of the first reflecting film of the first lens; the optical fiber assembly, the first lens and the second lens are all arranged in the probe shell; a dichroic coating that selectively transmits OCT light and totally reflects confocal light is coated in the middle of the front face of the second lens.

The OCT confocal common-path dual-mode endoscopic probe is characterized in that the diameter of the antireflection film is matched with the diameter and the emergence angle of the optical fiber assembly, and all light emergent from the optical fiber assembly is not contacted with the first reflecting film due to the diameter of the matched transmission film.

The OCT confocal common-path dual-mode endoscopic probe comprises a first reflecting film on a first lens, wherein the first reflecting film on the first lens is provided with a curvature radius which enables confocal light to obtain a focal length, an aberration and a numerical aperture which are completely different from those of OCT light.

The OCT confocal common-path dual-mode endoscopic probe comprises an optical fiber module, a beam shaping module, a common-path light splitting module and a confocal light path module, wherein the optical fiber module comprises an optical fiber beam for projecting confocal light and OCT light, the beam shaping module comprises a self-focusing lens for collimating or converging the OCT light and the confocal light at a small angle, the common-path light splitting module comprises a right-angle triangular prism, a dichroic coating film for selectively transmitting the OCT light and totally reflecting the confocal light is plated on a prism inclined plane of the right-angle triangular prism, and the confocal light path module comprises a dove prism with two curved surfaces.

The OCT confocal common-path dual-mode endoscopic probe further comprises a converging module for converging and projecting light transmitted by the common-path light splitting module onto a measured object, and the converging module is arranged in a probe shell.

The OCT confocal common-path dual-mode endoscopic probe is characterized in that a protruding structure for separating a beam shaping module, a common-path light splitting module and a converging module is arranged in the probe shell.

The OCT confocal common-path dual-mode endoscopic probe comprises a probe shell, wherein the inner wall of the probe shell is blacked, scattered light is absorbed by sand blasting, and the front end of the probe shell is transparent.

An imaging method of an OCT confocal common-path dual-mode endoscopic probe, which comprises the following steps:

s1: the OCT light and the confocal light are emitted through the optical fiber module;

s2: the OCT light and the confocal light projected from the optical fiber module are subjected to beam expansion and shaping through the beam shaping module;

s3: the beam-expanded and shaped OCT light and the confocal light are screened by a common-path light splitting module, so that a confocal light path and an OCT light path are separated;

s4: the confocal light independently passes through the confocal light path module and then is overlapped with the OCT light again through the common path light splitting module.

The imaging method of the OCT confocal common-path dual-mode endoscopic probe further comprises the following steps of S5: the confocal light path and the OCT light path which are overlapped together are converged and emitted through the converging module, so that the numerical aperture difference of the OCT light and the confocal light is formed.

The invention has the beneficial effects that: the invention provides an OCT confocal common-path dual-mode endoscopic probe and an imaging method, wherein a common-path light splitting module separates a confocal light path from an OCT light path, the confocal light path is changed by the confocal light path module and then overlapped with the OCT light path by the common-path light splitting module, and common-path output is realized by sharing a part of optical lenses, so that the requirement on the lens size is reduced, and the probe is miniaturized without correcting a moving image; the common-path structure is adopted, so that the endoscopic probe is small in size and simple to process, and the probe is convenient to share with the existing endoscope imaging channel, so that multi-mode imaging is realized; based on confocal imaging and OCT imaging characteristics, a common-path scanning probe is designed, and the structural characteristics of the common-path scanning probe are not easy to interfere in the same environment, so that the system stability is remarkably enhanced, real-time imaging can be realized, and a correction algorithm is not needed; the technical scheme is not only suitable for biological tissue detection imaging and optical-mechanical-electrical system measurement in industry, but also suitable for object imaging of other micro structures.

Drawings

Fig. 1 is a schematic structural view of an OCT confocal and common-path bimodal endoscopic probe according to embodiment 1 of the present invention.

Fig. 2 is a schematic structural view of an OCT confocal and common-path dual-mode endoscope probe according to embodiment 2 of the present invention.

Figure 3 is a flow chart of the steps of the imaging method of the OCT confocal, common-path, dual-mode endoscopic probe of the present invention.

Detailed Description

Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary only for explaining the present invention and are not to be construed as limiting the present invention.

In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more of the described features. In the description of the present invention, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.

In the description of the present invention, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically connected, electrically connected or can be communicated with each other; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.

In the present invention, unless expressly stated or limited otherwise, a first feature "above" or "below" a second feature may include both the first and second features being in direct contact, as well as the first and second features not being in direct contact but being in contact with each other through additional features therebetween. Moreover, a first feature being "above," "over" and "on" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature is higher in level than the second feature. The first feature being "under", "below" and "beneath" the second feature includes the first feature being directly under and obliquely below the second feature, or simply means that the first feature is less level than the second feature.

The following disclosure provides many different embodiments, or examples, for implementing different features of the invention. In order to simplify the present disclosure, components and arrangements of specific examples are described below. They are, of course, merely examples and are not intended to limit the invention. Furthermore, the present invention may repeat reference numerals and/or letters in the various examples, which are for the purpose of brevity and clarity, and which do not themselves indicate the relationship between the various embodiments and/or arrangements discussed. In addition, the present invention provides examples of various specific processes and materials, but one of ordinary skill in the art will recognize the application of other processes and/or the use of other materials.

As shown in fig. 1, an OCT confocal and confocal dual-mode endoscope probe, involves OCT and confocal, and the two optical paths can be output in a common path, including:

the optical fiber module is used for connecting the optical path to realize the bidirectional transmission of light;

the beam shaping module expands and shapes the OCT light and the confocal light projected from the optical fiber module;

a common-path light-splitting module which selectively transmits or reflects OCT light and confocal light by using a dichroic film, wherein the module is also a part of optical paths of the OCT light and the confocal light;

a confocal optical path module, in which only the confocal light is transmitted, so that the confocal light obtains completely different focal length, aberration and numerical aperture characteristics from the OCT light;

the converging module is used for converging and projecting the light transmitted by the common-path light splitting module onto a measured object;

the optical fiber module, the beam shaping module, the common-path light splitting module, the confocal optical path module and the converging module are all arranged in the probe shell; the OCT light path and the confocal light path are overlapped together after being integrated by the common-path light splitting module, and are converged and emitted by the converging module, so that the numerical aperture difference of the OCT light and the confocal light is formed.

The converging module converges the OCT light rays and the confocal light rays 7 emitted from the common-path light splitting module on the optical axis thereof to realize common-path output, but the converging module is not necessary in the OCT confocal common-path dual-mode endoscopic probe, namely the converging module is not required to be arranged in the OCT confocal common-path dual-mode endoscopic probe.

The OCT confocal common-path dual-mode endoscopic probe can realize common-path output by overlapping the confocal optical path and the OCT optical path and sharing a part of optical lenses, thereby reducing the requirement on the lens size, realizing the miniaturization of the probe and simultaneously avoiding the correction of moving images.

According to the OCT confocal and common-path dual-mode endoscope probe described above, the following examples are now exemplified:

example 1

As shown in fig. 1, the OCT confocal and common-path dual-mode endo-snoop head includes an optical fiber module, a beam shaping module, a common-path beam splitting module, a confocal optical path module and a convergence module, wherein the optical fiber module includes an optical fiber assembly 11, the common-path beam splitting module includes a second lens 16, and the convergence module includes a third lens 17; the upper end and the lower end of the front surface of the first lens 14 (the front surface of the first lens 14 is the surface of the first lens 14 close to the optical fiber assembly 11) are plated with first reflecting films 12, the middle part of the front surface of the first lens 14 is plated with an antireflection film, the antireflection film is positioned between the first reflecting film 12 at the upper end and the first reflecting film 12 at the lower end, the beam shaping module adopts the part of the first lens 14 plated with the antireflection film, and the confocal optical path module adopts the part of the first reflecting film 12 of the first lens 14; the fiber optic assembly 11, the first lens 14, the second lens 16, and the third lens 17 are all disposed within the probe housing 115; a dichroic coating 15 that selectively transmits OCT light and totally reflects confocal light is coated in the middle of the front face of the second lens 16 (the front face of the second lens 16 is the face of the second lens 16 close to the first lens 14); the third lens 17 converges the OCT light and the confocal light 7 emitted from the second lens 16 on the optical axis thereof, and realizes a common-path output.

In some embodiments, the optical fiber assembly 11 is fixed at the center of the probe housing 115, and the optical fiber assembly 11 and the probe housing 115 are fixed by dispensing.

In certain embodiments, the first lens 14, the second lens 16, and the third lens 17 are all fixed in the probe housing 115 by dispensing.

In some embodiments, the fiber optic assembly 11 employs a fiber optic bundle containing thousands to tens of thousands of fibers, with the light of the OCT light path and the confocal light path being projected from the fiber optic bundle of the fiber optic bundle 11.

In some embodiments, the fiber optic assembly 111 may also employ double-clad fibers.

In some embodiments, the first reflective film 12 is typically a gold film or a silver film, and may be an aluminum film or a dielectric film.

In some embodiments, the portion of the first lens 14 coated with the first reflective film 12 has a radius of curvature specifically designed to provide a substantially different focal length, aberration, and numerical aperture characteristic for the confocal beam than for the OCT beam.

In some embodiments, the diameter of the antireflection film depends on the diameter of the optical fiber assembly 11 and the size of the exit angle, so that all light exiting the optical fiber assembly 11 is not in contact with the first reflective film 12.

In certain embodiments, a protruding structure is provided inside the probe housing 115 for separating the first lens 14, the second lens 16, and the third lens 17; the inner wall of the probe housing 115 is blackened and sandblasted to absorb scattered light, and the front end of the probe housing 115 is made transparent so that light can pass through with as little loss as possible.

In fig. 1, a continuous straight line is an OCT optical path, and a broken line is a confocal optical path. Due to the presence of the dichroic coating 15, the confocal optical path and the OCT optical path are completely different, thus realizing that the high numerical aperture confocal optical path and the low numerical aperture OCT optical path are simultaneously realized in the same lens group and overlapped together.

In this embodiment, the imaging procedure of the OCT confocal and common-path dual-mode endoscope probe is as follows: firstly, a laser scanner couples OCT light into an optical fiber of the optical fiber assembly 11, the OCT light passes through central parts of the first lens 14, the second lens 16 and the third lens 17 respectively to form a converging light beam with low numerical aperture to be emitted, and the distance from the focal point of the OCT light to the third lens 17 is just 2 times of the distance from the focal point of the confocal light to the third lens 17; after the OCT light projection is completed, the laser scanner couples in confocal light into the optical fiber of the optical fiber assembly 11, which passes through the center of the first lens 14, reflects in front of the second lens 16 to the front of the first lens 14, passes through the second lens 16, and finally converges out through the third lens 17. Obviously, since the aperture of the confocal light is much larger than that of the OCT light, the structure can provide a large numerical aperture difference for two different wavelengths of light. Through the mode, the accurate overlapping of the OCT image and the confocal image at the same position is realized, and the image superposition and fusion are realized easily through an algorithm.

Example 2

As shown in fig. 2, the present OCT confocal and common-path dual-mode endo-snoop head includes an optical fiber module including an optical fiber bundle 18 for projecting the confocal light and the OCT light, a beam shaping module including a self-focusing lens 111 for collimating or converging the OCT light and the confocal light at a small angle, a common-path splitting module including a right-angle triangular prism 112, a dichroic coating film plated on a prism slope of the right-angle triangular prism 112 to selectively transmit the OCT light and totally reflect the confocal light, and a confocal optical path module including a dove prism 113 with two curved surfaces, the converging module including a fourth lens 114, the fourth lens 114 finally converging the OCT light and the confocal light 7 emitted from the right-angle triangular prism 112 onto its optical axis and eliminating chromatic aberration, realizing a common-path output.

In certain embodiments, the fiber optic bundle 18 is secured within the probe housing 116 by dispensing.

In certain embodiments, a protruding structure is provided inside the probe housing 116 for separating the beam shaping module, the common path splitting module and the converging module; the inner wall of the probe housing 116 is blackened and sandblasted to absorb scattered light, and the front end of the probe housing 116 is made transparent so that light can pass through with as little loss as possible.

In fig. 2, a continuous straight line is an OCT optical path, and a broken line is a confocal optical path.

In this embodiment, the imaging procedure of the OCT confocal and common-path dual-mode endoscope probe is as follows: the laser scanner transmits OCT light into the optical fiber bundle 18 through the optical fiber module, the OCT light passes through the self-focusing lens 111 to form parallel or small-angle converging light beams, the parallel or small-angle converging light beams are projected onto the inclined surface of the right-angle triangular prism 112, then reflected to the fourth lens 114 by the inclined surface of the right-angle triangular prism 112, and then converged into low-numerical aperture light through the fourth lens 114 to be emitted, wherein the distance from the focal point of the OCT light to the fourth lens 114 is just 2 times of the distance from the focal point of the confocal light to the fourth lens 114; at the same time, the laser scanner couples the confocal light into the optical fiber bundle 18 of the optical fiber module, the confocal light is converged by the self-focusing lens 111 after being emitted by the optical fiber bundle 18, passes through the right-angle triangular prism 112 again after being reflected by two curved surfaces of the dove prism 113, and then is emitted to the fourth lens 114 through the right-angle triangular prism 112, and is converged into high-numerical aperture light through the fourth lens 114; clearly, by controlling the radii of curvature and aspherical coefficients of the two curved surfaces of the dove prism 113, the numerical aperture difference of the OCT light and the confocal light can be controlled.

As shown in fig. 3, an imaging method of the OCT confocal and common-path dual-mode endoscopic probe described above specifically includes the following steps:

s1: the OCT light and the confocal light are emitted through the optical fiber module;

s2: the OCT light and the confocal light projected from the optical fiber module are subjected to beam expansion and shaping through the beam shaping module;

s3: the beam-expanded and shaped OCT light and the confocal light are screened by a common-path light splitting module, so that a confocal light path and an OCT light path are separated;

s4: the confocal light independently passes through the confocal light path module and then is overlapped with the OCT light again through the common path light splitting module;

s5: the confocal light path and the OCT light path which are overlapped together are converged and emitted through the converging module, so that the numerical aperture difference of the OCT light and the confocal light is formed.

Compared with the prior art, the technical scheme has the following advantages:

(1) After the confocal light path and the OCT light path are separated by utilizing the common-path light splitting module, the confocal light path and the OCT light path are overlapped together by the common-path light splitting module after the confocal light is changed by the confocal light path module, so that the requirement on the size of a lens is reduced, and the probe is miniaturized without correcting a moving image;

(2) The technical scheme adopts a common-path structure, so that the OCT common-focus common-path dual-mode endoscopic probe has small size and simple processing, is convenient for the probe to be shared with an imaging channel of the existing endoscope, and realizes multi-mode imaging.

(3) The technical scheme designs the common-path scanning probe based on the characteristics of confocal imaging and OCT imaging, and the structural characteristics of the common-path scanning probe are not easy to interfere in the same environment, so that the system stability is remarkably enhanced, real-time imaging can be realized, and a correction algorithm is not needed.

(4) The technical scheme is not only suitable for detecting and imaging biological tissues and measuring an optical-electromechanical system in industry, but also suitable for imaging objects with other micro structures.

In the description of the present specification, reference to the terms "one embodiment," "certain embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

It is to be understood that the invention is not limited in its application to the examples described above, but is capable of modification and variation in light of the above teachings by those skilled in the art, and that all such modifications and variations are intended to be included within the scope of the appended claims.