D-type microcapsule probe suitable for intravascular OCT imaging

Abstract

The invention discloses a D-type microcapsule probe suitable for intravascular OCT (optical coherence tomography) imaging. The probe comprises a single-mode optical fiber, a gradient refractive index optical fiber, an inclined-plane coreless optical fiber, refractive index matching glue and a D-type glass cap tube, the graded-index optical fiber is welded at one end of the single-mode optical fiber to serve as a micro-collimation / focusing lens; the bevel coreless optical fiber is welded to the other end of the gradient refractive index optical fiber and serves as a total reflection bevel; the head end of the optical fiber is arranged in the D-shaped glass cap tube, and the optical fiber and the inner wall of the D-shaped glass cap tube are filled with the refractive index matching glue; the outer tube wall of the D-shaped glass cap tube is subjected to flat-angle polishing to form a flat-angle mirror surface, and the reflection inclined plane of the coreless optical fiber is orthographically projected on the flat-angle mirror surface. According to the invention, through matching correction of the D-shaped optical capsule, transverse and radial photoetching resolutions are completely consistent in mechanical OCT spiral scanning 3D imaging, and astigmatism influence on imaging caused by the optical fiber and the cylindrical surface effect of the O-shaped optical capsule can be completely eliminated.

Description

Technical Field

[0001] The invention belongs to the technical field of medical devices, and in particular relates to a D-type microcapsule probe suitable for intravascular OCT imaging. Background Art

[0002] In recent years, intravascular OCT scanning (hereinafter referred to as IVOCT) imaging technology has developed rapidly. The structural design of the micro OCT probe suitable for human blood vessels (especially coronary arteries) is the key to determining the imaging performance. In the field of interventional endoscopic imaging, optical fiber is often required as the transmission medium of the optical signal waveguide. In order to obtain micron-level resolution, the laser scanning beam needs to be collimated / focused at the end of the optical fiber. Micro-fiber lens technology is a common technical method for commercial IVOCT today. The beam is focused through a gradient refractive index optical fiber, and then the optical path is folded through an inclined optical fiber. The optical path diameter is only 125μm, which is conducive to overall packaging. In terms of technology, the optical fiber fixed-length cutting, fusion splicing and polishing technology are relatively mature, and the consistency of the optical performance of the IVOCT probe is guaranteed.

[0003] Although the lens fiber technology has many advantages, it also has unavoidable drawbacks. Since the outer side of the lens fiber is a cylindrical surface, it will affect the side-outgoing light beam in a single direction, causing the original Gaussian circular spot to be distorted into an elliptical spot. This astigmatism caused by the cylindrical effect will greatly affect the OCT imaging results when it is serious. In order to compensate for the influence of the cylindrical effect of the lens fiber, the existing technical solution is to pre-embed the prepared lens fiber in an optical curing glue, also known as an optical capsule. The optical capsule not only serves as a lens protection sheath to protect the fragile lens fiber body, but also as a part of the optical path to compensate for the cylindrical effect of the lens fiber. The introduction of the optical capsule is equivalent to increasing the cylindrical diameter of the lens fiber, thereby reducing the influence of the cylindrical effect on the light beam in a single scanning direction. However, this method cannot completely eliminate the influence of the cylindrical effect, nor is it conducive to the output of the optical consistency of the IVOCT probe. In addition, the optical capsule prepared by curing the optical glue is affected by multiple factors such as temperature and material, and its shaping consistency and repeatability are difficult to guarantee. In addition, the traditional method of preparing such an OCT probe requires a lot of labor costs, which is a labor-intensive production process. This is also the reason why disposable IVOCT catheters are difficult to truly achieve mass production and large-scale market launch. Summary of the invention

[0004] The main purpose of the present invention is to overcome the shortcomings and deficiencies of the prior art and to provide a D-type microcapsule probe and imaging device suitable for intravascular OCT imaging. The present invention retains the technical advantages of optical shaping at the end of the lens fiber and completely eliminates the astigmatism problem caused by the cylindrical effect, thereby obtaining excellent optical consistency, system repeatability and imaging performance with isotropic resolution.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] In the first aspect, the present invention provides a D-type microcapsule probe suitable for intravascular OCT imaging, comprising a single-mode optical fiber, a gradient refractive index optical fiber, a beveled coreless optical fiber, a refractive index matching glue and a "D"-type glass cap tube; the gradient refractive index optical fiber is fused to one end of the single-mode optical fiber as a micro-collimation / focusing lens, the beveled coreless optical fiber is fused to the other end of the gradient refractive index optical fiber, and the bevel of the beveled coreless optical fiber serves as a total reflection bevel; the optical fiber head end is built into the "D"-type glass cap tube, and the refractive index matching glue fills the optical fiber and the inner wall of the "D"-type glass cap tube for curing, bonding and refractive index matching; the outer tube wall of the "D"-type glass cap tube is polished at a flat angle to form a flat mirror surface, and the reflection bevel of the coreless optical fiber is projected onto the flat mirror surface.

[0007] As a preferred technical solution, the bare fiber diameters of the single-mode optical fiber, the graded-index optical fiber and the beveled coreless optical fiber are equal.

[0008] As a preferred technical solution, the angle of the polished bevel of the coreless optical fiber is 40°-55°.

[0009] As a preferred technical solution, the polished bevel of the coreless optical fiber is coated with a reflective film layer, and light is emitted based on mirror-like reflection; the outer wall of the polished bevel of the coreless optical fiber is placed in the air, and light is emitted based on total internal reflection.

[0010] As a preferred technical solution, the refractive index matching glue, "D"-shaped glass cap tube, and coreless optical fiber are transparent materials with equal or similar refractive indices, and the laser beam transmitted in the medium is regarded as a uniform medium.

[0011] As a preferred technical solution, the optical fiber head end is pre-buried and cured in the center of a "D"-shaped glass cap tube with refractive index matching glue. The "D"-shaped glass cap tube serves as both a transparent imaging light window for optical correction and a protective sleeve for the bare fiber.

[0012] As a preferred technical solution, the light-emitting surface of the "D"-shaped optical capsule is an optical mirror, the lateral or radial angle of the mirror is 5-12°, and is parallel to the oblique projection surface of the coreless optical fiber.

[0013] As a preferred technical solution, the polished mirror surface of the "D"-shaped glass cap tube faces the outer side wall, and the mirror light exit window area covers and is larger than the diameter of the laser beam exit spot.

[0014] As a preferred technical solution, the light window width is 200-500 μm, and the maximum grinding and polishing depth is about 0.1 mm.

[0015] In a second aspect, the present invention provides an imaging device suitable for intravascular OCT imaging, including the D-type microcapsule probe suitable for intravascular OCT imaging.

[0016] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0017] Based on mature glass processing technology, the "D"-type optical capsule probe assembly of the present invention has the advantages of easy material acquisition and assembly, low cost and high repeatability, and the disposable intravascular OCT probe can be truly automated and mass-produced. After matching and correction by the "D"-type optical capsule, the bare fiber lens originally imaged by the cylindrical effect can output a high-quality circular Gaussian spot, so that in the mechanical OCT spiral scanning 3D imaging, the lateral and radial lithography resolutions are completely consistent, and the astigmatism caused by the optical fiber and the "O"-type optical capsule is completely eliminated. The solution of the present invention can completely solve the optical astigmatism problem of intravascular OCT imaging that has been plagued for a long time, and is expected to truly realize automated production. It is a "cost-effective" solution with great social and economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0019] Figure 1 This is a schematic diagram of the bare fiber structure of the optical fiber lens of the IVOCT probe in this embodiment; Figure 1 Part (a) is the front view of the bare fiber structure of the IVOCT probe optical fiber lens; Figure 1 Part (b) is the side view of the bare fiber structure of the IVOCT probe fiber lens; Figure 1 Part (c) is the light spot shape diagram of the bare fiber side of the IVOCT probe optical fiber lens;

[0020] Figure 2 It is a schematic diagram of the structure of an IVOCT probe based on an "O"-shaped optical capsule in the prior art; Figure 2 Part (a) is the front view of the IVOCT probe structure based on the “O”-shaped optical capsule; Figure 2 Part (b) is a side view of the IVOCT probe structure based on the “O”-shaped optical capsule; Figure 2 Part (c) shows the spot shape of the IVOCT probe based on the “O”-shaped light capsule;

[0021] Figure 3 This is a schematic diagram of the IVOCT probe structure based on a "D"-shaped glass light capsule in this embodiment; Figure 3 Part (a) is the front view of the IVOCT probe structure based on the “D”-shaped glass light capsule; Figure 3 Part (b) is a side view of the IVOCT probe structure based on the “D”-shaped glass light capsule; Figure 3 Part (c) in the figure shows the spot shape of the IVOCT probe based on the “D” type glass light capsule.

[0022] Description of reference numerals:

[0023] 1. Single-mode optical fiber, 2. Graded refractive index optical fiber, 3. Beveled coreless optical fiber, 4. Traditional "O" type optical capsule, 5. "D" type glass optical capsule, 6. Reflective film layer. DETAILED DESCRIPTION

[0024] In order to enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present application.

[0025] Reference to "embodiments" in this application means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described in this application may be combined with other embodiments.

[0026] See also Figure 1 Part (a), part (b), and part (c) in the figure, a specific embodiment of the present invention provides a D-type microcapsule probe suitable for intravascular OCT imaging, comprising a single-mode optical fiber 1, a gradient refractive index optical fiber 2, a beveled coreless optical fiber 3, a refractive index matching glue, and a "D"-type glass cap tube 5; the gradient refractive index optical fiber 2 is fused to one end of the single-mode optical fiber 1 as a micro-collimation / focusing lens, the beveled coreless optical fiber 3 is fused to the other end of the gradient refractive index optical fiber 2, the bevel of the beveled coreless optical fiber 3 is used as a total reflection bevel, and the bevel is polished; the optical fiber head end is built into the "D"-type glass cap tube, and the refractive index matching glue fills the optical fiber and the inner wall of the "D"-type glass cap tube 5 for curing bonding and refractive index matching; the outer tube wall of the "D"-type glass cap tube 5 is polished at a flat angle to form a flat mirror surface, and the reflection bevel of the beveled coreless optical fiber 3 is projected onto the flat mirror surface.

[0027] In a specific embodiment, the bare fiber diameters of the single-mode optical fiber 1, the gradient refractive index optical fiber 2, and the bevel coreless optical fiber 3 are equal. This design ensures that consistent light transmission performance can be provided when performing high-resolution intravascular imaging, and is conducive to simplifying the design and manufacturing process of the probe. In addition, such a design helps to improve the stability and reliability of the imaging system, so that information on the internal structure of the blood vessel can be obtained more accurately in clinical applications.

[0028] In a specific embodiment, the end of the coreless optical fiber of the present invention is polished into a bevel. In order to ensure the total reflection condition, the incident angle of the optical fiber is greater than 40°. At the same time, in order to ensure the efficiency of receiving reflected light, the angle is not greater than 55°. The polishing angle of the coreless optical fiber is 40°-55°.

[0029] It is understandable that the coreless optical fiber end of the present invention is carefully designed and precisely processed, and is precisely polished to a specific bevel angle. This innovative design is intended to optimize the transmission and reflection behavior of optical signals in the optical fiber, thereby improving the overall performance of the system.

[0030] Specifically, in order to ensure that the light beam is totally reflected at the interface between the coreless optical fiber and the air, this patent sets a lower limit for the incident angle, that is, the incident angle must be greater than 40°. This is because total reflection is a special phenomenon when a light beam is emitted from a light-dense medium (such as optical fiber material, which has a relatively high refractive index) into a light-sparse medium (such as air, which has a relatively low refractive index). When the incident angle is greater than a certain critical angle (40° in this case), the light beam will be almost completely reflected back into the original medium without entering the light-sparse medium. This feature is crucial to ensuring efficient transmission of optical signals in optical fibers.

[0031] However, simply satisfying the total reflection condition is not enough to ensure the best performance of the system. In order to further improve the reception efficiency of the reflected light, we also need to consider the propagation direction of the light beam after it is reflected from the end of the optical fiber. If the polishing angle is too large, the reflected light may deviate from the expected receiving range, resulting in optical signal loss. Therefore, we set an upper limit for the incident angle, that is, the angle is no greater than 55°. This limit ensures that the reflected light can be captured by the receiving device within a reasonable range, thereby improving the overall efficiency of the system.

[0032] Therefore, the polishing angle of the coreless optical fiber end is precisely controlled between 40° and 55°, which not only ensures that the light beam meets the total reflection condition at the optical fiber interface, but also ensures that the reflected light can be effectively received. This innovative design not only improves the transmission efficiency of optical signals, but also enhances the stability and reliability of the system, providing strong support for applications in optical communications, sensing, medical imaging and other fields.

[0033] In a more specific embodiment, the optical fiber probe includes a single-mode optical fiber 1 with an overall diameter of 125 μm, a gradient refractive index optical fiber 2, and a bevel coreless optical fiber 3. The gradient refractive index optical fiber 2 is of fixed length. The fixed-length gradient optical fiber collimates and focuses the light beam output by the single-mode optical fiber, and then folds through the total reflection bevel of the coreless optical fiber to realize the side output. The polishing bevel angle of the coreless optical fiber is 43°. At this time, the scanning beam is unevenly distributed on the Z axis and the X axis, presenting a shuttle shape.

[0034] It is understandable that graded-index fiber (GIF), also known as self-focusing fiber or gradient fiber, is a special type of optical fiber, the refractive index of the core region on its cross section is gradually or gradient distributed, usually gradually decreasing from the center to the edge according to a certain rule. The refractive index center of the graded-index fiber is the highest, and the refractive index gradually decreases with the increase of radial distance until it reaches the constant refractive index of the cladding. In this patent, a graded-index fiber 2 is used to connect the single-mode optical fiber 1 and the beveled coreless optical fiber 3, which can cause the light beam to automatically focus when propagating in the optical fiber, that is, the light beam will converge toward the central axis of the optical fiber to form a light ray similar to a sine wave, thereby reducing the divergence of the light beam and improving the transmission efficiency of the optical signal.

[0035] In a specific embodiment, due to the small area of ​​the polished bevel of the optical fiber, it is difficult to reserve an air gap to form a glass-air total reflection interface. Therefore, the polished bevel of the bevel coreless optical fiber is plated with a reflective film layer 6. The reflective film layer 6 is an optical curing glue with a lower refractive index than the coreless optical fiber. The light beam is incident from the light-dense glass to the light-sparse curing glue film layer, and the glass-glue interface forms a total reflection interface. In addition, this curing glue has the characteristics of dustproof and anti-falling, and can provide a stable total reflection condition.

[0036] In a specific embodiment, the optical fiber probe is embedded and solidified in the center of a "D" type optical glass capsule, and the optical capsule serves as both a transparent imaging light window and a protective sleeve. Compared with the traditional "O" type optical capsule 4, the "D" type changes the light emitting surface from a cylindrical surface to a mirror surface, eliminating the cylindrical effect of the optical capsule. In addition, see Figure 2 In parts (a), (b), and (c), the overall outer diameter of the "O"-shaped optical capsule is circular; and the D-type microcapsule probe of this embodiment has the advantage of small mass compared to traditional capsules, and can also meet the requirements of high-speed concentric rotation scanning, and is also suitable for spiral mechanical scanning.

[0037] More specifically, the light-emitting surface of the "D"-type optical capsule is an optical mirror. The angle of this mirror has been precisely calculated, and its lateral or radial angle is set to 5-12°. This specific angle selection is to optimize the direction and focusing effect of the light beam. Exemplarily, setting the lateral or radial angle of the optical mirror to 8° can optimize the direction and focusing effect of the light beam to a greater extent. It is worth noting that the mirror and the inclined projection surface of the coreless optical fiber remain parallel to each other. This geometric alignment ensures the linearity and consistency of the light beam during transmission, thereby improving the clarity and accuracy of intravascular OCT imaging. This parallel relationship is crucial to maintaining the stable performance of the system throughout the operation, and also helps to reduce image distortion problems caused by optical path deviation.

[0038] In a specific embodiment, see Figure 3 In part (a) and part (b), the lens optical fiber is pre-buried in the axis of the "D"-shaped glass light capsule 5, the reflective mirror is directly opposite to the light-emitting surface, and the side-emitting light beam is emitted along the center of the light-emitting surface. The light-emitting surface is a polished optical mirror surface, the light window width is 200-500μm, and the maximum grinding and polishing depth is about 0.1mm. Figure 3 In part (c), the shape of the probe structure spot in this embodiment is circular.

[0039] In a specific embodiment, the polished mirror surface of the "D"-shaped glass cap tube faces the outer side wall, and the mirror light exit window area covers and is larger than the laser beam exit spot diameter. This arrangement ensures that the laser beam can directly irradiate the polished mirror surface when passing through the cap tube, thereby achieving efficient reflection and focusing.

[0040] In another embodiment of the present application, an imaging device suitable for intravascular OCT imaging is provided, including a D-type microcapsule probe suitable for intravascular OCT imaging, wherein the D-type microcapsule probe includes a single-mode optical fiber, a gradient refractive index optical fiber, a beveled coreless optical fiber, a refractive index matching glue, and a "D"-type glass cap tube; the gradient refractive index optical fiber is fused to one end of the single-mode optical fiber as a micro-collimation / focusing lens, the beveled coreless optical fiber is fused to the other end of the gradient refractive index optical fiber, and the bevel of the beveled coreless optical fiber serves as a total reflection bevel; the optical fiber head end is built into the "D"-type glass cap tube, and the refractive index matching glue fills the optical fiber and the inner wall of the "D"-type glass cap tube for curing bonding and refractive index matching; the outer tube wall of the "D"-type glass cap tube is polished at a flat angle to form a flat mirror surface, and the reflection bevel of the coreless optical fiber is projected onto the flat mirror surface.

[0041] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0042] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A D-type microcapsule probe suitable for intravascular OCT imaging, characterized in that: It comprises a single-mode optical fiber, a gradient refractive index optical fiber, a beveled coreless optical fiber, a refractive index matching glue and a "D"-shaped glass cap tube; the gradient refractive index optical fiber is fused to one end of the single-mode optical fiber as a micro-collimation / focusing lens, the beveled coreless optical fiber is fused to the other end of the gradient refractive index optical fiber, and the beveled surface of the beveled coreless optical fiber serves as a total reflection beveled surface; the optical fiber head end is built into the "D"-shaped glass cap tube, and the refractive index matching glue fills the optical fiber and the inner wall of the "D"-shaped glass cap tube for curing bonding and refractive index matching; the outer tube wall of the "D"-shaped glass cap tube is polished at a flat angle to form a flat mirror surface, and the reflection bevel of the coreless optical fiber is orthographically projected onto the flat mirror surface.

2. A D-type microcapsule probe suitable for intravascular OCT imaging according to claim 1, characterized in that: The bare fiber diameters of the single-mode optical fiber, the graded-refractive-index optical fiber and the bevel-coreless optical fiber are equal.

3. A D-type microcapsule probe suitable for intravascular OCT imaging according to claim 1, characterized in that: The angle of the polished bevel of the coreless optical fiber is 40°-55°.

4. A D-type microcapsule probe suitable for intravascular OCT imaging according to claim 1 or 3, characterized in that: The polished bevel of the coreless optical fiber is plated with a reflective film layer, and light is emitted based on mirror-like reflection; the outer wall of the polished bevel of the coreless optical fiber is placed in the air, and light is emitted based on total internal reflection.

5. A D-type microcapsule probe suitable for intravascular OCT imaging according to claim 1, characterized in that: The refractive index matching glue, "D"-shaped glass cap tube, and coreless optical fiber are transparent materials with equal or similar refractive indices, and the transmission of the laser beam in the medium is regarded as a uniform medium.

6. A D-type microcapsule probe suitable for intravascular OCT imaging according to claim 1, characterized in that: The optical fiber head end is pre-buried and cured in the center of the "D"-shaped glass cap tube through refractive index matching glue. The "D"-shaped glass cap tube serves as both a transparent imaging light window for optical correction and a protective sleeve for the bare fiber.

7. A D-type microcapsule probe suitable for intravascular OCT imaging according to claim 1, characterized in that: The light-emitting surface of the "D"-shaped optical capsule is an optical mirror surface, the lateral or radial angle of the mirror surface is 5-12°, and is parallel to the oblique projection surface of the coreless optical fiber.

8. The D-type microcapsule probe suitable for intravascular OCT imaging according to claim 1, characterized in that: The polished mirror surface of the "D"-shaped glass cap tube faces the outer side wall, and the mirror light exit window area covers and is larger than the diameter of the laser beam exit spot.

9. A D-type microcapsule probe suitable for intravascular OCT imaging according to claim 8, characterized in that: The light window width is 200-500 μm, and the maximum grinding and polishing depth is about 0.1 mm.

10. An imaging device suitable for intravascular OCT imaging, characterized in that: A D-type microcapsule probe suitable for intravascular OCT imaging comprising any one of claims 1-9.

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