Miniature endoscopic probe with adjustable focal length

Abstract

The invention discloses a focal length adjustable miniature endoscopic probe, which comprises a transparent packaging tube, an all-fiber structure probe, a matching liquid adjusting system, a driving motor and an interface, and is characterized in that the transparent packaging tube is of a transparent structure and plays roles in protecting the all-fiber structure probe and sealing matching liquid; the all-fiber structure probe is an imaging element for collecting and transmitting optical signals and is composed of a single-mode optical fiber, a coreless optical fiber, a multimode optical fiber and an inclined-plane coreless optical fiber, and the matching liquid adjusting system comprises a container for storing matching liquid, a conveying pipeline and a micro pump or a valve for controlling flowing of the matching liquid. According to the micro endoscopic probe with the adjustable focal length, continuous and accurate adjustment of the focal length is achieved through the focusing liquid, clear imaging can be conducted on targets at various depths and positions, the detection accuracy is improved, a complex mechanical focusing structure is avoided, the design of the endoscopic probe is more concise and compact, the focal length can be adjusted in real time according to actual needs, and the detection accuracy is improved. The endoscopic probe does not need to be replaced, and operation steps are reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of endoscope probes, and specifically to a micro endoscope probe with adjustable focal length. Background Art

[0002] The ultra-fine optical fiber endoscope probe is a tool for internal detection using optical fiber technology, with an extremely fine probe diameter and high flexibility. Its diameter size is generally less than 1 mm, that is, the diameter of the encapsulation tube is less than 1 mm, and the diameter of the optical fiber probe inside is 125 microns, which can perform high-definition observation and detection in a narrow space;

[0003] For example, the publication number CN112336291A discloses a micro endoscope probe with multimodality. By setting a group of lenses, the endoscope lens simultaneously has confocal and OCT modes, making it possible to set three modalities of wide-field white light, confocal microscopy, and OCT in an endoscope lens with a certain volume limit; by setting a PZT scanning tube, compared with the mainstream galvanometer system, the size of the endoscope probe is reduced, making the whole endoscope probe practical and compact in volume; and by using a micro camera module with a much smaller size than the traditional camera module, the size of the endoscope probe is further reduced; this micro endoscope probe has the characteristics of anti-interference, simplicity and ease of use, compact structure, and fast switching;

[0004] For example, the publication number CN103091830A discloses a micro DC power endoscope inspection device. The top of the outer shell is provided with a light-emitting diode, the cathode pin of the light-emitting diode is fixedly connected to a wedge-shaped bracket, a phosphor layer is formed on the surface of the LED chip on the upper part of the wedge-shaped bracket, the phosphor layer is electrically connected to the anode pin of the light-emitting diode through a metal wire, a foggy scattering resin lens is formed on the inner wall of the light-emitting diode, a pin fixing column is fixedly provided below the light-emitting diode, a battery is fixedly provided at the lower end of the pin fixing column, the anode pin is electrically connected to the positive electrode of the battery, and the anode pin is electrically connected to the inner wall of the outer shell; a rotary switch is provided at the bottom end of the outer shell, and a spring is formed in the hole at the upper part of the rotary switch; a sealing gasket is formed at the middle part of the rotary switch near the concave card slot of the outer shell, and the bottom of the outer shell tightly presses the sealing gasket; its overall structure is simple, easy to carry, and has good waterproof performance, and is suitable for various occasions lacking power supply and with strict requirements for fire prevention and explosion protection;

[0005] However, the existing endoscope probes have certain limitations in focal length adjustment. Usually, each ultra-fine optical fiber endoscope probe has a unique focal length value, which is difficult to meet the high-precision imaging detection under complex-shaped pores. For example, the above-listed comparative patents have this problem;

[0006] Therefore, we provide a micro endoscope probe with adjustable focal length to solve the problems raised above. Summary of the Invention

[0007] The object of the present invention is to provide a microendoscopic probe with adjustable focal length, so as to solve the problem that the existing ultra-fine optical fiber endoscopic probe has certain limitations in focal length adjustment. Usually, each ultra-fine optical fiber endoscopic probe has a unique focal length value, which is difficult to meet the high-precision imaging detection under complex-shaped pores.

[0008] To achieve the above object, the present invention provides the following technical solution: A microendoscopic probe with adjustable focal length, comprising a transparent encapsulation tube, an all-fiber structure probe head, a matching liquid adjustment system, a driving motor and an interface;

[0009] It further includes:

[0010] The transparent encapsulation tube is of a transparent structure, which plays a role in protecting the all-fiber structure probe head and sealing the matching liquid. The focusing performance of the all-fiber structure probe head is represented by three parameters: working distance, focused spot size and depth of field;

[0011] Among them, the working distance represents the distance between the focused spot position of the all-fiber probe head and the output end face of the probe head, which characterizes the best distance position that the probe head can detect;

[0012] The focused spot size represents the waist diameter of the focused spot of the all-fiber probe head, which characterizes the lateral resolution of the probe head;

[0013] The depth of field represents twice the Rayleigh length after the all-fiber probe head is focused, which characterizes the effective detection range of the probe head;

[0014] The all-fiber structure probe head is an imaging element for collecting and transmitting optical signals, which is composed of "single-mode fiber + coreless fiber + multi-mode fiber + beveled coreless fiber";

[0015] Among them, the single-mode fiber is used to connect the backend device, transmit the light provided by the light source to the endoscopic probe, and transmit the optical signal collected by the endoscopic probe back to the signal processing unit. Moreover, the coreless fiber is made of high-purity silica and only has a cladding and a coating structure;

[0016] The overall refractive index of the coreless fiber structure is uniformly distributed;

[0017] The multi-mode fiber is a graded-index multi-mode fiber, which enables the probe head to have the function of focusing the light beam;

[0018] The beveled coreless fiber is used to change the outgoing direction of the detection light by plating a metal reflection film on the bevel, so as to realize the collection of lateral signals;

[0019] The matching liquid adjustment system includes a container for storing the matching liquid, a delivery pipeline, and a micro pump or valve for controlling the flow of the matching liquid.

[0020] Adopting the above technical solution, the continuous and precise adjustment of the focal length is realized by using the focusing liquid, which can clearly image the targets at various depths and positions, improve the accuracy of detection, avoid complex mechanical focusing structures, make the design of the endoscopic probe more concise and compact, can adjust the focal length in real time according to actual needs, without replacing the endoscopic probe, and reduce the operation steps.

[0021] As a preferred technical solution of the present invention, the all-fiber structure probe has focusing performance, and at the same time can irradiate the light of the system light source, collect the light reflected and scattered from the detection part, transmit the collected signal light back to the signal processing unit, and realize imaging by using an algorithm.

[0022] Adopting the above technical solution, through the all-fiber structure probe having focusing performance, and at the same time can irradiate the light of the system light source, collect the light reflected and scattered from the detection part, transmit the collected signal light back to the signal processing unit, and realize imaging by using an algorithm. Due to the focusing performance of the all-fiber structure probe, it is convenient to realize imaging by using an algorithm.

[0023] As a preferred technical solution of the present invention, the multimode fiber is a graded-index fiber and has focusing characteristics.

[0024] Adopting the above technical solution, the multimode fiber is a graded-index fiber and has focusing characteristics, which enables the all-fiber structure probe to have focusing performance.

[0025] As a preferred technical solution of the present invention, the driving motor is used to rotate the fiber probe to realize scanning imaging.

[0026] Adopting the above technical solution, by using the driving motor to rotate the fiber probe to realize scanning imaging, it is convenient to drive the probe to rotate and achieve the effect of scanning imaging.

[0027] As a preferred technical solution of the present invention, the computer precisely controls the matching liquid to enter or flow out of a specific area at the front end of the probe by using a wireless control method;

[0028] Change the refractive index of the area to realize the adjustment of the focal length.

[0029] Adopting the above technical solution, by precisely controlling the matching liquid to enter or flow out of a specific area at the front end of the probe;

[0030] Change the refractive index of the area to realize the adjustment of the focal length, which is convenient for adjusting the focal length.

[0031] As a preferred technical solution of the present invention, the interface is used to connect with external devices.

[0032] Adopting the above technical solution, by using the interface to connect with external devices, it is convenient to connect the probe with external devices.

[0033] As a preferred technical solution of the present invention, the interface transmits the information of the measured sample obtained by the probe to an external device through a transmission line to achieve data transmission and interaction of control signals.

[0034] With the above technical solution, the interface transmits the information of the measured sample obtained by the probe to an external device through a transmission line to achieve data transmission and interaction of control signals, facilitating data transmission.

[0035] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0036] 1. In the present invention, by setting a transparent encapsulation tube and a probe with an all-fiber structure, the probe with an all-fiber structure is an imaging element for collecting and transmitting optical signals, which is composed of "single-mode fiber + coreless fiber + multi-mode fiber + beveled coreless fiber". The probe formed by this structure has focusing performance, and at the same time can irradiate the light of the system light source, collect the light reflected and scattered from the detection part, transmit the collected signal light back to the signal processing unit, and realize imaging by using an algorithm; the encapsulation tube is transparent, playing a role in protecting the fiber probe and sealing the matching liquid.

[0037] 2. In the present invention, by setting a matching liquid adjustment system and a driving motor, the matching liquid adjustment system is a key part of this design, which includes components such as a container for storing the matching liquid, a delivery pipeline, and a micro pump or valve for controlling the flow of the matching liquid; the driving motor is used to rotate the fiber probe to achieve scanning imaging. By precisely controlling the matching liquid to enter or flow out of a specific area at the front end of the probe, the refractive index of this area is changed, thereby realizing the adjustment of the focal length.

[0038] 3. In the present invention, by setting an interface, it is connected to an external device through the interface to achieve data transmission and interaction of control signals. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation to the present invention. In the drawings:

[0040] Figure 1 is a front view structural schematic diagram of the present invention;

[0041] Figure 2 is a bottom view structural schematic diagram of the present invention;

[0042] Figure 3 is a top view sectional structural schematic diagram of the present invention;

[0043] Figure 4 is a structural schematic diagram of the endoscopic probe composition of the present invention

[0044] Figure 5 is a working principle structural schematic diagram of the present invention;

[0045] Figure 6 Schematic diagram of the focusing characteristic structure of the present invention;

[0046] Figure 7 Simulation diagram of the beam propagation scenario when the refractive index of the matching liquid of the present invention is 1.5;

[0047] Figure 8 Simulation diagram of the beam propagation scenario when the refractive index of the matching liquid of the present invention is 1.44.

[0048] In the figure: 1, transparent encapsulation tube; 2, all-fiber structure probe; 3, matching liquid adjustment system; 4, drive motor; 5, interface. Specific implementation manner

[0049] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0050] Please refer to Figures 1-8 , the present invention provides the following technical solutions.

[0051] In order to solve the problem that there are certain limitations in the focal length adjustment of the existing ultra-fine fiber endoscope probe in the prior art. Usually, each ultra-fine fiber endoscope probe has a unique focal length value, which is difficult to meet the high-precision imaging detection under complex-shaped pores. Therefore, in this embodiment, through the following technical solutions, a micro endoscope probe with adjustable focal length is provided, which is provided with a transparent encapsulation tube 1, an all-fiber structure probe 2, a matching liquid adjustment system 3, a drive motor 4 and an interface 5, as Figure 1 , Figure 2 , Figure 3 and Figure 4 shown. The transparent encapsulation tube 1 is a transparent structure, which plays a role in protecting the all-fiber structure probe 2 and sealing the matching liquid;

[0052] The all-fiber structure probe 2 is an imaging element for collecting and transmitting optical signals. It is composed of "single-mode fiber + coreless fiber + multimode fiber + beveled coreless fiber", and the multimode fiber is a multimode gradient-index fiber with focusing characteristics. The all-fiber structure probe 2 is an imaging element for collecting and transmitting optical signals, and it is composed of "single-mode fiber + coreless fiber + multimode fiber + beveled coreless fiber". Among them, the single-mode fiber is used to connect the backend device, transmit the light provided by the light source to the endoscope probe, and transmit the optical signal collected by the endoscope probe back to the signal processing unit. The coreless fiber is made of high-purity silica and has only a cladding and a coating structure, without a fiber core structure. The overall refractive index is uniformly distributed, which is equivalent to a glass fiber with a uniform refractive index distribution and is used to expand the detection light, which can increase the working distance of the probe. The multimode fiber is selected as a graded-index multimode fiber to enable the probe to have the function of focusing the light beam. The beveled coreless fiber is used to change the outgoing direction of the detection light by plating a metal reflection film on the bevel, so as to realize the collection of lateral signals.

[0053] The focusing performance of the all-fiber structure probe 2 can be represented by three parameters: working distance, focusing spot size, and depth of field. The working distance represents the distance between the focusing spot position of the all-fiber probe and the output end face of the probe, which characterizes the best distance position that the probe can detect. The focusing spot size represents the waist diameter of the focusing spot of the all-fiber probe, which characterizes the lateral resolution of the probe. The depth of field represents twice the Rayleigh length after the all-fiber probe is focused, which characterizes the effective detection range of the probe.

[0054] The matching liquid adjustment system 3 includes a container for storing the matching liquid, a delivery pipeline, and a micro pump or valve for controlling the flow of the matching liquid. The multimode fiber is a multimode gradient-index fiber with focusing characteristics. The probe composed of this structure has focusing performance. At the same time, it can irradiate the light from the system light source, collect the light reflected and scattered from the detection part, transmit the collected signal light back to the signal processing unit, and use algorithms to achieve imaging. The transparent encapsulation tube 1 is transparent and serves to protect the all-fiber structure probe 2 and seal the matching liquid. The matching liquid adjustment system 3 includes a container for storing the matching liquid, a delivery pipeline, and a micro pump or valve for controlling the flow of the matching liquid. And the driving motor 4 is used to rotate the fiber probe to achieve scanning imaging. The driving motor 4 drives the micro coupler to rotate by means of gear transmission, and the maximum rotation angle is 180 degrees in both positive and negative directions. When the coupler rotates, it drives the encapsulation tube and the fiber probe to rotate together to achieve circular scanning imaging. At the same time, the driving motor 4 precisely controls the matching liquid to enter or flow out of a specific area at the front end of the probe, changes the refractive index of the area, and realizes the adjustment of the focal length. Moreover, the transmission line is used to transmit the information of the measured sample obtained by the probe to an external device, and the interface 5 is used to connect to the external device to achieve data transmission and the interaction of control signals.

[0055] The structural model and focusing characteristics of a micro-endoscopic probe are simulated using the finite element optical simulation method. By constructing different refractive indices of the matching liquid, the working distance and the change of light field intensity of the endoscope probe are analyzed. The beam propagation scenario of the probe with the structure of "single-mode fiber + coreless fiber + multi-mode fiber + beveled coreless fiber" is constructed through the COMSOL wave optics module, as Figure 7 and Figure 8 shown. When the refractive index of the matching liquid is 1.5 and the mixing ratio of tetrahydronaphthalene to absolute ethanol is about 7:3, the maximum electric field intensity value obtained at the focal point is 12495 V / m, and the working distance is 0.49 mm; as Figure 8 shown. When the refractive index of the matching liquid is 1.44 and the volume ratio of tetrahydronaphthalene to absolute ethanol is about 42.6% and 57.4%, the maximum electric field intensity value obtained at the focal point is 12671 V / m, and the working distance is 0.52 mm.

[0056] When the focal length needs to be adjusted, by inputting the required focal length, the micro-pump or valve can be automatically controlled through a pre-written algorithm, so that the matching liquid with a specific refractive index enters or exits a specific area at the front end of the probe through the delivery pipeline. The entry or exit of the matching liquid will change the optical properties of this area, thereby adjusting the focal length of the endoscope probe so that it can clearly present the image of the target tissue;

[0057] For example, when detecting micro-deep holes with irregular internal shapes, the amount of the matching liquid can be finely adjusted according to the characteristics of different depths and positions inside the known holes to obtain the best imaging effect;

[0058] For example, when detecting micro-deep holes with unknown internal shapes, after inserting the endoscope probe, the matching liquid adjustment function can be directly started, so that the refractive index of the matching liquid changes within the adjustable range to obtain the best imaging effect. Specific examples are shown in Figure 4 and Figure 5 shown;

[0059] For example, two liquids, tetrahydronaphthalene and absolute ethanol, are used to prepare a refractive index matching liquid. By changing the mixing ratio of tetrahydronaphthalene and absolute ethanol, different refractive indices can be obtained between 1.361 and 1.541. When the proportion of tetrahydronaphthalene increases, the refractive index of the mixture will gradually approach 1.541; conversely, when the proportion of absolute ethanol increases, the refractive index of the mixture will gradually approach 1.361. Different two liquids can be selected according to different situations, and there are also many different liquid combinations for modulation, and different refractive index ranges can be obtained;

[0060] Among them, the focal length of the probe can be deduced by using the complex parameter representation of the Gaussian beam and the ABCD law. Furthermore, the micro pump or valve can be controlled to mix AB liquids in different proportions to obtain matching liquid refractive indices with different values. Among them, the wavelength of the incident Gaussian beam provided by the light source is λ, the waist radius is ω0, the length of the coreless fiber is L0, the refractive index is n0, the length of the multimode fiber is L, the central refractive index is n1, the focusing constant is g, the right-angled side length of the coreless fiber with a beveled surface coated with a reflective film is L1, the refractive index is n0, the end face is at a distance L2 from the wall of the encapsulation tube, the wall thickness is h, the refractive index of the encapsulation tube is n2, the inner diameter of the encapsulation tube is Ri, the outer diameter of the encapsulation tube is Ro, f is the focal length, n3 is the refractive index of the matching liquid inside the sealed tube, and n4 is the refractive index of the air outside the sealed tube, that is, n4 = 1.

[0061] Construct the ABCD matrix according to the structure of the fiber endoscope probe as follows:

[0062]

[0063] The obtained A, B, C, and D in the transformation matrix are respectively:

[0064]

[0065]

[0066]

[0067]

[0068] Among them,

[0069]

[0070]

[0071]

[0072]

[0073] According to the properties of the Gaussian beam, it can be known from the complex parameter representation that:

[0074]

[0075] Among them,

[0076] The functional relationship between the focal length f of the endoscope probe and the refractive index n3 of the matching liquid can be deduced, and then f can be adjusted by changing n3.

[0077] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A micro endoscopy probe with adjustable focal length, comprising a transparent packaging tube (1), an all-fiber structure probe (2), a matching liquid adjustment system (3), a drive motor (4) and an interface (5); It is characterized in that Also includes: The transparent packaging tube (1) is a transparent structure, which plays the role of protecting the all-fiber structure probe (2) and sealing the matching liquid. The focusing performance of the all-fiber structure probe (2) is represented by three parameters: working distance, focusing spot size and depth of field. Among them, the working distance refers to the distance between the focus spot position of the all-fiber probe and the output end face of the probe, which represents the best distance position that the probe can detect; The focused spot size indicates the focused spot waist diameter of the all-fiber probe, which characterizes the lateral resolution of the probe. The depth of field represents twice the Rayleigh length of the all-fiber probe after focusing, which characterizes the effective detection range of the probe; The all-fiber structure probe (2) is an imaging element for collecting and transmitting optical signals, and is composed of "single-mode optical fiber + coreless optical fiber + multi-mode optical fiber + inclined coreless optical fiber"; Among them, the single-mode optical fiber is used to connect the back-end equipment and transmit the light provided by the light source to the endoscopic probe. The endoscopic probe transmits the collected optical signal back to the signal processing unit. The coreless optical fiber is made of high-purity silica and has only a cladding and coating structure. The overall refractive index of the coreless fiber structure is uniformly distributed; The multimode optical fiber is a graded-index multimode optical fiber, which enables the probe to focus the light beam; The inclined coreless optical fiber is used to change the emission direction of the detection light by coating a metal reflective film on the inclined surface, thereby realizing lateral signal collection; The matching liquid regulating system (3) comprises a container for storing the matching liquid, a delivery pipeline, and a micro pump or valve for controlling the flow of the matching liquid.

2. The micro endoscope probe with adjustable focal length according to claim 1, characterized in that: The all-fiber structure probe (2) has focusing performance, and can simultaneously radiate light from the system light source and collect light reflected and scattered from the detection part, transmit the collected signal light back to the signal processing unit, and realize imaging using an algorithm.

3. The micro endoscope probe with adjustable focal length according to claim 1, characterized in that: Multimode optical fiber is a graded-index optical fiber with focusing properties.

4. The micro endoscope probe with adjustable focal length according to claim 1, characterized in that: The drive motor (4) is used to rotate the optical fiber probe to achieve scanning imaging, and the drive motor (4) drives the micro-connector to rotate by means of gear transmission, with a maximum rotation angle of 180 degrees in both the forward and reverse directions. When the connector rotates, it drives the packaging tube and the optical fiber probe to rotate together to achieve annular scanning imaging.

5. The micro endoscope probe with adjustable focal length according to claim 4, characterized in that: By precisely controlling the matching fluid to enter or flow out of a specific area at the front end of the probe; By changing the refractive index of the area, the focal length can be adjusted.

6. The micro endoscope probe with adjustable focal length according to claim 1, characterized in that: The interface (5) is used for connecting to an external device.

7. The micro endoscope probe with adjustable focal length according to claim 6, characterized in that: The interface (5) transmits the measured sample information acquired by the probe to an external device via a transmission line, so as to realize the interaction of data transmission and control signals.

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