Fiber optic scanning endoscope based on electrostatic force drive
Through the electrostatically driven fiber scanning endoscope, the scanning optical fiber is driven by the electrostatically driven by the electrode sheet and the conductive dielectric layer, which solves the problem of poor control accuracy of the micro-endoscope and realizes high-precision inspection of micro-organs such as the pancreas and bile ducts. , improves image quality and reduces damage to patients.
Patent Information
- Application Number
- CN202210102142.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-01-27
- Publication Date
- 2024-12-13
- Estimated Expiration
- 2042-01-27
AI Technical Summary
Existing micro-endoscopy has poor control accuracy in the examination of tiny organs or tissues such as the pancreas and bile ducts, resulting in unclear images and harm to the patient.
Using an electrostatic power-driven fiber scanning endoscope, the scanning fiber is calculated by distributing multiple electrode sheets and conductive dielectric layers on the inner wall of the shell, and the scanning fiber is driven by electrostatic power, combined with voltage detection and controller for precise position control. Offset for high-precision scanning.
High-precision drive and position control of the micro-endoscope are achieved, image quality is improved, patient pain is reduced, and patient harm is reduced.
Smart Images
Figure CN114403780B_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of medical devices. Background Art
[0002] At present, in the examination of gastric diseases, doctors usually use an endoscope inserted into the human body. Through the endoscope, the mucosal state of the esophagus, stomach, duodenal bulb and even the descending part can be clearly observed in sequence, and pathological and cytological examinations of living bodies can be performed. Gastroscopy is reliable and safe. In the intestinal examination, the doctor inserts the endoscope through the anus into the ileocecal cavity and observes the colon lesions from the mucosal side. Colonoscopy can meet the examination needs of almost all colon areas.
[0003] However, in the examination of tiny organs or tissues such as the pancreas and bile duct, imaging techniques such as B-ultrasound, CT or ERCP are usually used. Among them, endoscopic retrograde cholangiopancreatography (ERCP) is a method of inserting an endoscope into the descending part of the duodenum, finding the papilla of the pancreatic and bile duct opening, inserting a contrast catheter through the biopsy hole, and injecting iodine contrast agent for X-ray examination. The above methods have problems such as unclear observation images and easy harm to patients.
[0004] If the examination of tiny organs or tissues can be directly observed using an endoscope like a gastrointestinal examination, it can not only improve the image quality and facilitate the doctor's diagnosis, but also relieve the patient's pain and reduce the harm to the patient. However, the pancreatic duct is very narrow, with a diameter of only a few millimeters, which is impossible to perform using an existing endoscope with an outer diameter of about 10 mm. Therefore, a micro endoscope is needed, but the existing endoscope control methods are not suitable for the drive and position control of micro endoscopes, and the existing endoscope control methods have the problem of poor control accuracy when applied to micro endoscope control. Summary of the invention
[0005] The purpose of the present invention is to solve the problem of poor control accuracy in the existing micro-endoscope control, and proposes an optical fiber scanning endoscope driven by electrostatic force.
[0006] The optical fiber scanning endoscope based on electrostatic force drive of the present invention comprises: a housing, a conductive medium layer, a lens, a scanning optical fiber, an optical fiber bracket, n electrode sheets, n voltage sources, a voltage detection device and a controller; wherein n is an integer, and n≥2;
[0007] The shell is a cylindrical structure with openings at both ends. A lens is embedded at one end of the cylindrical structure, and an optical fiber holder is provided at the other end. The optical fiber holder is a circular structure with a central opening. The front end of the scanning optical fiber passes through the central hole of the circular structure to the inside of the shell, and the front end of the scanning optical fiber is adjacent to the lens. The surface of the scanning optical fiber is coated with a conductive medium layer.
[0008] The n electrode sheets are all rectangular and are attached to the inner wall of the shell, and the long sides of the n electrode sheets are parallel to the axis of the shell;
[0009] The n electrode sheets are connected to the positive electrodes of the n voltage sources one by one through wires, and the conductive medium layer is connected to the negative electrodes of the n voltage sources at the same time; the control signal input terminals of all the voltage sources are connected to the voltage control signal output terminals of the controller;
[0010] The voltage detection device is used to collect the voltage between the n electrode sheets and the conductive medium layer;
[0011] The controller is used to calculate the offset of the scanning optical fiber according to the current in the n electrode sheets, the voltage between the n electrode sheets and the conductive medium layer, and the frequency.
[0012] Furthermore, in the present invention, the controller is also used to control the output voltage of the voltage source according to the offset and target position of the scanning optical fiber until the scanning optical fiber reaches the target position.
[0013] Furthermore, in the present invention, the controller calculates the offset of the scanning optical fiber according to the current in the n electrode sheets, the voltage between the n electrode sheets and the conductive medium layer, and the frequency as follows:
[0014] The n electrode sheets and the conductive medium layer are equivalent to n capacitors, using the formula:
[0015] i=-2πfC×U(t)sin(2πf×t)
[0016] The capacitance value of each equivalent capacitor is calculated, where i is the current in the electrode sheet, f is the frequency of the voltage source; C is the equivalent capacitance value between the electrode sheet and the conductive medium layer, and U(t) is the voltage between the electrode sheet and the conductive medium layer;
[0017] Reuse:
[0018]
[0019] The distance between each electrode sheet and the conductive medium layer is calculated, where ε is the dielectric constant between the electrode sheet and the conductive medium layer, S is the facing area between the electrode sheet and the conductive medium layer, and d is the distance between the electrode sheet and the conductive medium layer;
[0020] Finally, the offset of the scanning optical fiber is obtained by using the distance between the n electrode sheets and the conductive medium layer.
[0021] The present invention has a simple structure and uses electrostatic force to drive the scanning optical fiber, which meets the requirements of the endoscope for the size of the driving structure. In addition, the present invention equates the electrode sheet and the conductive medium layer to a capacitor, thereby obtaining the distance between the electrode sheet and the conductive medium layer, and obtains the offset of the optical fiber according to the distance between the conductive medium layer and the electrode sheet. The position of the optical fiber is controlled according to the offset to achieve scanning. This method does not require a large driving structure, and only needs to change the output voltage of the voltage source to achieve control of the optical fiber. It has a simple structure and high precision, and can perform closed-loop control on the position of the scanning optical fiber to avoid nonlinear response of the scanning optical fiber under open-loop control, causing image distortion or limiting the frame rate. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Figure 1 is a schematic structural diagram of the optical fiber scanning endoscope driven by electrostatic force according to the present invention;
[0023] Figure 2 It is a schematic diagram of the scanning optical fiber position of the optical fiber scanning endoscope driven by electrostatic force in the initial state of the present invention;
[0024] Figure 3 It is a schematic diagram of the position of the scanning optical fiber of the optical fiber scanning endoscope driven by electrostatic force after movement of the present invention;
[0025] Figure 4 It is a control principle block diagram of the optical fiber scanning endoscope based on electrostatic force drive according to the present invention;
[0026] Figure 5 The driving signals output by two voltage sources in the X-axis direction;
[0027] Figure 6 The driving signals output by two voltage sources in the Y-axis direction;
[0028] Figure 7 This is the trajectory diagram of the scanning optical fiber movement. DETAILED DESCRIPTION
[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0030] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.
[0031] Specific implementation method 1: The following is combined Figure 1The present embodiment is described. The optical fiber scanning endoscope driven by electrostatic force described in the present embodiment comprises: a housing 2, a conductive medium layer 3, a lens 4, a scanning optical fiber 5, an optical fiber bracket 6, n electrode sheets 7, n voltage sources 8, a voltage detection device 9 and a controller 10; wherein n is an integer, and n≥2;
[0032] The housing 2 is a cylindrical structure with openings at both ends. A lens 4 is embedded at one end of the cylindrical structure, and an optical fiber bracket 6 is provided at the other end. The optical fiber bracket is a circular structure with a central opening. The front end of the scanning optical fiber 5 passes through the central hole of the circular structure to the inside of the housing 2, and the front end of the scanning optical fiber 5 is adjacent to the lens 4; the surface of the scanning optical fiber 5 is coated with a conductive medium layer 3;
[0033] The n electrode sheets 7 are all rectangular and are attached to the inner wall of the housing 2. The long sides of the n electrode sheets 7 are parallel to the axis of the housing 2.
[0034] The n electrode sheets 7 are connected to the positive electrodes of the n voltage sources 8 one by one through the wires 1, and the conductive medium layer 3 is connected to the negative electrodes of the n voltage sources 8 at the same time; the control signal input terminals of all the voltage sources 8 are connected to the voltage control signal output terminals of the controller 10;
[0035] The voltage detection device 9 is used to collect the voltage between the n electrode sheets 7 and the conductive medium layer 3;
[0036] The controller 10 is used to calculate the offset of the scanning optical fiber 5 according to the current in the n electrode sheets, the voltage between the n electrode sheets 7 and the conductive medium layer 3, and the frequency.
[0037] Furthermore, in this embodiment, the controller 10 is also used to control the output voltage of the voltage source 8 according to the offset and target position of the scanning optical fiber 5 until the scanning optical fiber 5 reaches the target position.
[0038] The present invention adopts electrostatic force driving, with the static position of the scanning optical fiber coated with the conductive medium as the center, and multiple (no less than 2, for example 4) electrodes are placed around. Figure 4 As shown in the figure, the central scanning optical fiber is plated with a conductive medium to form a central electrode. When voltage is applied to the central electrode and the surrounding electrodes, the central electrode will be affected by the electrostatic force of the surrounding electrodes. By applying different voltages, the central scanning optical fiber can be driven to produce different displacements.
[0039] The equivalent capacitance method is used for detection. The surrounding electrodes have equivalent capacitance to the central electrode. Since the capacitance value is proportional to the equivalent area of the electrode and inversely proportional to the equivalent distance between the electrodes, when the scanning optical fiber coated with a conductive medium is located at the center, the capacitance value is equal, and when it deviates from the center, the capacitance value is unequal. By real-time detection of each equivalent capacitance, the deviation position of the scanning optical fiber coated with a conductive medium can be obtained through the relationship between capacitance and position.
[0040] Further, in this embodiment, the controller 10 calculates the offset of the scanning optical fiber 5 according to the current in the n electrode sheets, the voltage between the n electrode sheets 7 and the conductive medium layer 3, and the frequency as follows:
[0041] The n electrode sheets 7 and the conductive medium layer 3 are equivalent to n capacitors, using the formula:
[0042] i=-2πfC×U(t)sin(2πf×t)
[0043] The capacitance value of each equivalent capacitor is calculated, wherein i is the current in the electrode sheet 7, f is the frequency of the voltage source 8; C is the equivalent capacitance value between the electrode sheet 7 and the conductive medium layer 3, and U(t) is the voltage between the electrode sheet 7 and the conductive medium layer 3;
[0044] Reuse:
[0045]
[0046] The distance between each electrode sheet 7 and the conductive medium layer 3 is calculated, wherein ε is the dielectric constant between the electrode sheet 7 and the conductive medium layer 3, S is the facing area between the electrode sheet 7 and the conductive medium layer 3, and d is the distance between the electrode sheet 7 and the conductive medium layer 3;
[0047] Finally, the offset of the scanning optical fiber is obtained by using the distance between the n electrode sheets 7 and the conductive medium layer 3 .
[0048] Furthermore, in this embodiment, the housing 2 is made of insulating material.
[0049] Furthermore, in this embodiment, the portion of the scanning optical fiber 5 located inside the housing 2 is coated with a conductive medium layer 3 .
[0050] Furthermore, in this embodiment, the voltage source has a voltage range of 30V to 100V.
[0051] Furthermore, in this embodiment, the initial position of the scanning optical fiber 5 in the housing 2 coincides with the central axis of the housing 2 .
[0052] As attached Figure 1 The figure shows a schematic diagram of the structure of a fiber optic scanning endoscope based on electrostatic force drive and equivalent capacitance detection. A scanning optical fiber coated with a conductive medium is fixed on an optical fiber bracket, and four electrodes are evenly distributed in a circular tubular shell, and insulating materials are filled between each electrode.
[0053] As attached Figure 2 As shown, at the initial moment, the scanning optical fiber coated with a conductive medium layer is located at the center of the cylindrical shell.
[0054] As attached Figure 3 As shown, under the action of electrostatic force, the scanning optical fiber 5 coated with the conductive medium layer 3 will produce displacement. Applying different voltage values can cause the scanning optical fiber 5 coated with the conductive medium layer 3 to produce different displacements, that is, the electrostatic force driving of the scanning optical fiber 5 is realized.
[0055] In the present invention, the amplitude of the output voltage of the voltage source can be preset according to the displacement and direction actually required, so as to control the scanning optical fiber to scan according to the set trajectory.
[0056] As attached Figure 4 As shown in FIG. 1 , a control method for driving the scanning optical fiber movement is shown. Four different voltages V1, V2, V3, and V4 are applied to the conductive medium layer 3 and the four electrode sheets in the housing 2 through the wire 1. Figure 5 As shown in FIG. 1 , the amplitude of the voltage difference of the electrode sheets in the horizontal direction X is modulated in a cosine triangle wave mode. Figure 6 As shown in FIG. 1 , the amplitude of the voltage difference of the electrode sheets in the vertical direction Y is modulated in a sinusoidal triangular wave mode. Figure 7 As shown, under the combined action of the electrostatic force in the horizontal direction X and the electrostatic force in the vertical direction Y, the scanning optical fiber 5 coated with the conductive medium layer 3 will form a spiral scanning track.
[0057] When the scanning optical fiber 5 is located at the center of the shell, the equivalent capacitance values of the four electrode sheets in the shell 2 and the conductive medium layer are equal; when deviating from the center, the capacitance values of the four electrode sheets in the shell 2 and the conductive medium layer are not equal. Therefore, the voltage difference between the electrode sheets in the horizontal direction X and the electrode sheets in the vertical direction Y generates an electrostatic force to drive the central scanning optical fiber 5 to move; the position is fed back by using the relationship between the size of the equivalent capacitance and the position of the scanning optical fiber 5, and the feedback is linearized by using a controller to eliminate nonlinear effects, thereby avoiding image distortion or limiting the frame rate caused by the nonlinear response of the scanning optical fiber 5 under open-loop control. The above process constitutes a closed-loop control, which ensures that the scanning optical fiber 5 can perform spiral scanning under control and obtain a clear image of the inspected organ or tissue through the lens 4.
[0058] Although the present invention is described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the present invention. It should therefore be understood that many modifications may be made to the exemplary embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims. It should be understood that the various dependent claims and features described herein may be combined in a manner different from that described in the original claims. It should also be understood that features described in conjunction with individual embodiments may be used in other described embodiments.
Claims
1. Fiber optic scanning endoscope driven by electrostatic force, It is characterized in that It includes: A housing (2), a conductive medium layer (3), a lens (4), a scanning optical fiber (5), an optical fiber bracket (6), n electrode sheets (7), n voltage sources (8), a voltage detection device (9) and a controller (10); wherein n is an integer and n≥2; The housing (2) is a cylindrical structure with two ends open, a lens (4) is embedded in one end of the cylindrical structure, and an optical fiber holder (6) is provided at the other end, the optical fiber holder (6) is a circular structure with a central opening, the front end of the scanning optical fiber (5) passes through the central hole of the circular structure to the interior of the housing (2), and the front end of the scanning optical fiber (5) is adjacent to the lens (4); the surface of the scanning optical fiber (5) is coated with a conductive medium layer (3); The n electrode sheets (7) are all rectangular and are attached to the inner wall of the shell (2); the long sides of the n electrode sheets (7) are all parallel to the axis of the shell (2); The n electrode sheets (7) are connected to the positive electrodes of the n voltage sources (8) in a one-to-one correspondence through the wires (1), and the conductive medium layer (3) is simultaneously connected to the negative electrodes of the n voltage sources (8); the control signal input terminals of all the voltage sources (8) are connected to the voltage control signal output terminals of the controller (10); The voltage detection device (9) is used to collect the voltage between the n electrode sheets (7) and the conductive medium layer (3); The controller (10) is used to calculate the offset of the scanning optical fiber (5) according to the current in the n electrode sheets, the voltage between the n electrode sheets (7) and the conductive medium layer (3), and the frequency; the controller (10) also pre-sets the amplitude of the output voltage of the voltage source according to the target displacement and direction, so as to control the scanning optical fiber to scan according to the set trajectory; The controller (10) calculates the offset of the scanning optical fiber (5) according to the current in the n electrode sheets, the voltage between the n electrode sheets (7) and the conductive medium layer (3), and the frequency as follows: The n electrode sheets (7) and the conductive medium layer (3) are equivalent to n capacitors, using the formula: i=-2πfC×U(t)sin(2πf×t) The capacitance value of each equivalent capacitor is calculated, wherein i is the current in the electrode sheet (7), f is the frequency of the voltage source (8); C is the equivalent capacitance value between the electrode sheet (7) and the conductive medium layer (3), and U(t) is the voltage between the electrode sheet (7) and the conductive medium layer (3); Reuse: Calculating and obtaining the distance between each electrode sheet (7) and the conductive medium layer (3), wherein ε is the dielectric constant between the electrode sheet (7) and the conductive medium layer (3), S is the facing area between the electrode sheet (7) and the conductive medium layer (3), and d is the distance between the electrode sheet (7) and the conductive medium layer (3); Finally, the offset of the scanning optical fiber is obtained by using the distance between the n electrode sheets (7) and the conductive medium layer (3).
2. The optical fiber scanning endoscope driven by electrostatic force according to claim 1, It is characterized in that The controller (10) is also used to control the output voltage of the voltage source (8) according to the offset and target position of the scanning optical fiber (5) until the scanning optical fiber (5) reaches the target position.
3. The optical fiber scanning endoscope driven by electrostatic force according to claim 1, It is characterized in that The shell (2) is made of insulating material.
4. The optical fiber scanning endoscope driven by electrostatic force according to claim 1 or 2, It is characterized in that The portion of the scanning optical fiber (5) located inside the housing (2) is coated with a conductive medium layer (3).
5. The optical fiber scanning endoscope driven by electrostatic force according to claim 1, It is characterized in that The voltage source voltage range is 30V~100V.
6. The electrostatically driven optical fiber scanning endoscope according to claim 1, It is characterized in that The initial position of the scanning optical fiber (5) in the housing (2) coincides with the central axis of the housing (2).