Telescopic varifocal self-rotating OCT (optical coherence tomography) scanning probe

Abstract

A telescopic varifocal self-rotating OCT (optical coherence tomography) scanning probe belongs to the technical field of industrial surface imaging and comprises a casing large sleeve, a casing small sleeve, a probe and a miniature hollow motor. The shell large sleeve is an outermost layer straight sleeve, and the transparent short sleeve is adhered to the tail end of the shell large sleeve. The small sleeve is arranged in the large sleeve of the shell, the probe is arranged in the small sleeve, and the small sleeve is adhered to the motor sleeve; the probe comprises an optical fiber, a capillary glass tube, a self-focusing lens and a plano-convex lens which are sequentially arranged along the optical fiber in the direction from light incidence to a to-be-detected sample, and the probe part is bonded through optical cement. The tail end of the right side of the micro hollow motor is bonded with the reflecting prism, and the tail end of the left side of the micro hollow motor leads out a wire. According to the invention, the rotation of the hollow shaft of the micro hollow motor is controlled to drive the reflecting prism adhered to the tail end of the hollow shaft to rotate, so that the light path is changed, the drop point of the focused light beam is adjusted, the rapid circumferential scanning of various hole cavities is realized, and the imaging quality, the measurement capability and the measurement efficiency are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of industrial surface imaging, and relates to a telescopic zoom spin-type OCT scanning probe. Background Art

[0002] Optical Coherence Tomography (OCT) is based on the Michelson interferometry technology. The interference signal of light is converted into relative depth information through Fourier transform to obtain three-dimensional data of the shallow surface layer of the sample to be measured. An OCT system usually has a reference arm and a sample arm. The laser emitted from the light source is divided into two beams by a beam splitter. One beam is directed to the reference arm, and a plane mirror is installed on the reference arm. The beam is reflected by the mirror and returns along the original path. The other beam is directed to the sample arm, and the sample to be measured is placed on the sample arm. The beam is reflected by the sample and returns along the original path. The two returned beams interfere with each other, and the relative depth information of each layer on the sample surface can be obtained through Fourier transform.

[0003] A mechanism is required at the sample arm end to collimate and converge the light beam from the light source and obtain the optical signal reflected from the sample surface. It is usually called a probe. The outer shell is made of flexible materials such as silica gel or rigid materials such as metal, and is internally provided with optical fibers for transmitting optical signals and lenses for collimation and convergence. Existing probes usually use non-hollow motors, and the reflecting prism is placed between the motor and the lens, resulting in problems such as occlusion at the connection of the outer shell and the motor wires, and the imaging quality is affected to a certain extent. In addition, existing probes usually need to rotate as a whole to achieve circumferential scanning, so a large radial jump will be introduced, reducing the imaging quality.

[0004] Some design methods of endoscopic probes based on OCT technology have been proposed, for example:

[0005] In an OCT probe design method proposed in Chinese invention patent ZL200410080280.8, the reflecting prism is rotated by a micro motor to change the optical path. However, due to the wires of the micro motor will cause a certain occlusion to the optical path, the imaging quality is affected to a certain extent.

[0006] In an OCT probe design method proposed in Chinese invention patent ZL202021885332.X, the rotation of the probe is controlled by internal metal wires. However, this operation method is relatively difficult to control the accuracy and speed of rotation, and will cause a large radial jump to the entire probe, further affecting the imaging quality. Summary of the Invention

[0007] To overcome the deficiencies of the prior art, the present invention provides a telescopic variable-focus spin-type scanning probe. By placing a micro hollow motor at the end of the spin-type scanning probe to drive the rotating prism, circumferential scanning is achieved, thus avoiding the radial jump caused by the overall rotation of the probe and significantly improving the imaging quality.

[0008] To solve the technical problems existing in the prior art, the technical solution adopted by the present invention is as follows:

[0009] A telescopic variable-focus spin-type OCT scanning probe, the telescopic variable-focus spin-type OCT scanning probe comprising an outer shell large sleeve 1, a small sleeve 9, a probe 15 and a micro hollow motor 12. The outer shell large sleeve 1 is the outermost straight tube sleeve, and a transparent sleeve 14 is bonded to the end thereof using optical glue. The transparent sleeve 14 has a left-open and right-closed structure. The small sleeve 9 is placed in the outer shell large sleeve 1 and is bonded to the motor sleeve 11 for positioning, and the probe 15 is placed inside the small sleeve 9. The probe 15 includes, arranged in sequence (from left to right) along the optical fiber 3 from the direction of light incidence to the sample to be measured, with the sample to be measured on the right side and the optical fiber 3 on the left side: an optical fiber 3, a capillary glass tube 5, a self-focusing lens 7, and a plano-convex lens 8. Each component of the probe 15 is bonded using optical glue, and the end of the probe 15 away from the sample is positioned with the small sleeve 9 through a stepped structure. The micro hollow motor 12 is placed in a motor sleeve 11 of the same size. A reflecting prism 13 is bonded to the right end of the micro hollow motor 12, and the reflecting prism 13 extends into the transparent sleeve 14. A lead wire 10 is led out from the left end of the micro hollow motor 12, and the lead wire 10 is led out through the outer circular groove of the small sleeve 9.

[0010] Further, the outer shell large sleeve 1 is straight, with smooth inner and outer surfaces without grooves. The right end face of the outer shell large sleeve 1 is bonded with a lens sleeve 14 using optical glue. The transparent sleeve 14 has the same inner and outer diameters as the outer shell large sleeve 1 and is coaxially aligned.

[0011] Further, the small sleeve 9 is straight. To enable the micro hollow motor lead wire 10 to smoothly lead out from the left side of the outer shell large sleeve 1 and be connected to an external power source, a through groove with a width of 0.5 mm and a depth of 0.5 mm is opened on the outer cylindrical surface of the small sleeve 9. At the same time, to avoid interference between the right end face of the small sleeve 9 and the micro hollow motor lead wire 10, a block with a camber height of 0.8 mm is cut off from the right end face of the small sleeve 9, and the cut-off part is coaxially aligned with the through groove. The small sleeve 9 is placed inside the outer shell large sleeve 1, and the two can slide smoothly and stably between them.

[0012] Further, the probe 15 further includes a probe sleeve 2, a self-focusing lens sleeve 6, and a plano-convex lens sleeve 4; the probe sleeve 2 is provided at the leftmost end of the small sleeve 9; the optical fiber 3 penetrates into the probe sleeve 2 from the left side and exits from the right side, and the end of the optical fiber 3 is inserted into the capillary glass tube 5; the capillary glass tube 5 and the self-focusing lens 7 are jointly placed in the self-focusing lens sleeve 6; the left end face of the capillary glass tube 5 is aligned with the left end face of the self-focusing lens sleeve 6, and the right end face of the capillary glass tube 5 is located inside the self-focusing lens sleeve 6; the self-focusing lens 7 and the capillary glass tube 5 are placed at intervals, and the right end face of the self-focusing lens 7 extends out of the right end face of the self-focusing lens sleeve 6.

[0013] Further, the probe sleeve 2 is positioned away from the sample end and the small sleeve 9 through a stepped structure.

[0014] Further, the left end face of the capillary glass tube 5 is coaxially connected to the right end face of the probe sleeve 2.

[0015] Further, the left end of the plano-convex lens sleeve 4 is inserted into the probe sleeve 2, and the right end is inserted into the plano-convex lens 8.

[0016] Further, the left side of the plano-convex lens 8 is a convex surface and the right side is a flat surface.

[0017] Further, the right end face of the capillary glass tube 5 is inclined, and the inclination angle is 8° clockwise perpendicular to the end face along the radial direction. The left end face of the self-focusing lens 7 is also inclined, and the left end face of the self-focusing lens 7 is parallel to the right end face of the capillary glass tube 5. The capillary glass tube 5 and the self-focusing lens 7 are arranged at intervals.

[0018] Further, the center of the right side of the capillary glass tube 5 is located at the focal position of the self-focusing lens 7. The light beam diverges from the end of the optical fiber 3, is collimated by the self-focusing lens 7, and exits parallel from the right side of the self-focusing lens 7.

[0019] Further, the micro hollow motor 12 includes a motor body, a hollow shaft 16, and a wire 10. The wire 10 is located on the left outer circular end face of the micro hollow motor 12 with a diameter of 0.42 mm; the hollow shaft 16 is hollow inside with an inner diameter of 0.64 mm; the outer diameter of the motor housing is 2.4 mm.

[0020] Further, a reflecting prism 13 is connected to the right end face of the hollow shaft 16 of the micro hollow motor 12, and the reflecting prism 13 is an internal reflecting prism.

[0021] Further, the reflecting plane of the reflecting prism 13 forms a certain angle with the axis of the micro hollow motor 12, and the angle range is between 30° and 60°.

[0022] Furthermore, an anti-reflection film is provided on the surface of the self-focusing lens 7, an anti-reflection film is provided on the surface of the plano-convex lens 8, and a high-reflection film is provided on the reflecting surface of the reflecting prism 13. The system light source is input into the optical fiber 3, and then diverges from the end of the optical fiber 3 and is collimated by the self-focusing lens 7. After collimation, the light beam is incident parallel into the plano-convex lens 8, and then the light beam is converged by the plano-convex lens 8 to achieve focusing. It is obliquely reflected by the reflecting prism 13 and incident on the surface of the sample to be measured through the transparent sleeve 14. During measurement, the hollow shaft 16 of the micro hollow motor 12 rotates, driving the reflecting prism 13 to rotate, so as to realize the circumferential scanning measurement of the sample to be measured. The distance between the inner surface of the sample to be measured and the central axis of the spin-type OCT scanning probe is 12 mm - 18 mm.

[0023] Furthermore, the sample to be measured is a round hole, a square hole or a cavity structure.

[0024] Furthermore, the spin-type OCT scanning probe can be axially fed under the load of a moving platform to realize the circumferential scanning measurement of the sample to be measured.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] (1) By introducing the micro hollow motor 12, controlling the rotation of its hollow shaft 16, driving the reflecting prism 13 to rotate, the present invention changes the optical path, thereby adjusting the landing point of the focused light beam. At the same time, it is axially fed under the load of an external moving platform to realize the rapid circumferential scanning of round holes, square holes and cavity structures.

[0027] (2) The present invention introduces the micro hollow motor 12, which can avoid the radial runout introduced by the overall rotation of the probe 15 and improve the imaging quality. At the same time, the light beam passes through the hollow shaft 16 of the micro hollow motor and is reflected by the reflecting prism 13 and directly acts on the surface of the workpiece, thereby avoiding the imaging artifacts caused by the micro motor wire 10 and improving the imaging quality, measurement ability and measurement efficiency.

[0028] (3) The rotation speed of the micro hollow motor 12 in the present invention can reach up to 10000 rpm at most, which is suitable for scenarios with higher requirements for scanning speed. Description of the Drawings

[0029] Figure 1 is the basic structure diagram of the spin-type OCT scanning probe provided by the present invention;

[0030] Figure 2 is the structural schematic diagram of the micro hollow motor;

[0031] Figure 3 is the working principle diagram of the spin-type scanning probe; Figure 3In (a), (b), (c), and (d), they are respectively the working principle diagrams of the hollow motor when it rotates 0°, 90°, 180°, and 270° in the working state;

[0032] Figure 4 It is a schematic structural diagram of the probe;

[0033] Figure 5 It is the optical path diagram of the spin-type OCT scanning probe provided by the present invention, Figure 5 In (a), (b), (c), and (d), they are respectively the optical path diagrams of the hollow motor when it rotates 0°, 90°, 180°, and 270° in the working state;

[0034] In the figure: 1 outer shell large sleeve; 2 probe sleeve; 3 optical fiber; 4 plano-convex lens sleeve; 5 capillary glass tube; 6 self-focusing lens sleeve; 7 self-focusing lens; 8 plano-convex lens; 9 small sleeve; 10 wire; 11 motor sleeve; 12 micro hollow motor; 13 reflecting prism; 14 transparent sleeve; 15 probe; 16 micro motor hollow shaft. Specific embodiments

[0035] The following further describes the structure of the invention in combination with the accompanying drawings and the preferred specific embodiments of the present invention. It should be noted that, on the premise of no conflict, any combination of the following described embodiments or technical features can form a new embodiment.

[0036] As Figure 1 shown, the present invention provides a telescopic zoom spin-type OCT scanning probe, and the spin-type OCT scanning probe includes an outer shell large sleeve 1, a small sleeve 9, a probe 15, and a micro hollow motor 12. The outer shell large sleeve 1 is the outermost straight tube sleeve, and the transparent sleeve 14 is bonded to the end using optical glue. The transparent sleeve 14 has a left-open and right-closed structure; the small sleeve 9 is placed in the outer shell large sleeve 1 and is bonded to the motor sleeve 11 for positioning, and the probe 15 is placed inside the small sleeve 9; the probe 15 includes, arranged in sequence (from left to right) along the optical fiber 3 from the direction of light incident to the sample to be measured, where the sample to be measured is located on the right side and the optical fiber 3 is located on the left side: optical fiber 3, capillary glass tube 5, self-focusing lens 7, plano-convex lens 8. Each component of the probe 15 is bonded using optical glue, and the end of the probe 15 away from the sample is positioned with the small sleeve 9 through a stepped structure. The micro hollow motor 12 is placed in a motor sleeve 11 of the same size. The right end of the micro hollow motor 12 is bonded with a reflecting prism 13, and the reflecting prism 13 extends into the transparent sleeve 14. The left end of the micro hollow motor 12 leads out a wire 10, and the wire 10 is led out through the outer circular groove of the small sleeve 9. The outer shell large sleeve 1 is straight, and the inner and outer surfaces are smooth without grooves. The right end face of the outer shell large sleeve 1 is bonded with a lens sleeve 14 using optical glue. The transparent sleeve 14 has the same inner and outer diameters as the outer shell large sleeve 1 and is coaxially aligned.

[0037] In this embodiment, the small sleeve 9 is in a straight cylindrical shape. In order to enable the wire 10 of the micro hollow motor to smoothly lead out from the left side of the large outer sleeve 1 of the housing and be connected to an external power supply, a through groove with a width of 0.5 mm and a depth of 0.5 mm is opened on the outer cylindrical surface of the small sleeve 9. At the same time, in order to avoid interference between the right end face of the small sleeve 9 and the wire 10 of the micro hollow motor, a block with a camber height of 0.8 mm is cut off at the right end face of the small sleeve 9, and the cut-off part is coaxially aligned with the through groove. The small sleeve 9 is placed inside the large outer sleeve 1 of the housing, and the two can slide smoothly and stably between them.

[0038] As Figure 2 shown, the micro hollow motor 12 includes a motor main body, a hollow shaft 16 and a wire 10. The wire 10 is located on the left outer circular end face of the micro hollow motor 12, with a diameter of 0.42 mm. The external controller transmits electrical signals through the wire 10 to control its rotation; the inside of the hollow shaft 16 is hollow, enabling it to pass a light beam of a certain size, with an inner diameter of 0.64 mm; the outer diameter of the motor housing is 2.4 mm. During operation, the hollow shaft 16 of the micro hollow motor rotates, while the housing and the main body do not rotate.

[0039] The micro hollow motor 12 is placed in the micro hollow motor sleeve 11, and a reflecting prism 13 is bonded to the right end face of its hollow shaft 16. The reflecting prism 13 is an internal reflecting prism, and the reflecting plane of the reflecting prism 13 forms a 45° angle with the axis of the micro hollow motor 12, so that the reflecting prism 13 perpendicularly reflects the light beam. When the micro hollow motor 12 drives the reflecting prism 13 to rotate, the focal point of the light beam can fall on different positions of the cavity. The working principle diagrams when the micro hollow motor 12 rotates 0°, 90°, 180°, and 270° are as Figure 3 (a), (b), (c), and (d) shown, that is, circumferential scanning of the cavity is realized, and the optical path diagrams corresponding to each angle are as Figure 5 (a), (b), (c), and (d) shown.

[0040] The probe includes a probe sleeve 2, an optical fiber 3, a capillary glass tube 5, a self-focusing lens 7, a plano-convex lens 8, a self-focusing lens sleeve 6, and a plano-convex lens sleeve 4. The optical fiber passes through from the left side of the probe sleeve 2 and exits from the right side. The end of the optical fiber 3 is inserted into the capillary glass tube 5. The capillary glass tube 5 and the self-focusing lens 7 are jointly placed in the self-focusing lens sleeve 6. The left end face of the capillary glass tube 5 is aligned with the left end face of the self-focusing lens sleeve 6, and the self-focusing lens 7 and the capillary glass tube 5 are placed at intervals. The end of the probe sleeve 2 away from the sample is positioned with the small sleeve 9 through a stepped structure.

[0041] In this embodiment, the left end face of the capillary glass tube 5 is coaxially bonded to the right end face of the probe sleeve 2. The left end of the plano-convex lens sleeve 4 is inserted into the probe sleeve 2, and the right end is inserted into the plano-convex lens 8. The left side of the plano-convex lens 8 is a convex surface, and the right side is a flat surface. The right end face of the capillary glass tube 5 is inclined clockwise by 8°, the left end face of the self-focusing lens 7 is inclined clockwise by 8°, and the right end face of the capillary glass tube 5 is parallel to the left end face of the self-focusing lens 7. The center of the right side of the capillary glass tube 5 is located at the focal position of the self-focusing lens 7. The light beam diverges from the end of the optical fiber, is collimated by the self-focusing lens 7, and exits parallel from the right side of the self-focusing lens 7.

[0042] In this embodiment, the surface of the self-focusing lens 7 has an anti-reflection film, and the surface of the plano-convex lens 8 has an anti-reflection film; the reflecting surface of the reflecting prism 13 has an anti-reflection film.

[0043] In this embodiment, after the sample light beam diverges from the optical fiber 3, it is collimated by the self-focusing lens 7, focused by the plano-convex lens 8. After the focused light beam passes through the micro hollow motor 12, it is obliquely reflected by the reflecting prism 13 at the end of the shaft of the micro hollow motor 12 and is incident on the sample surface. Under the drive of the micro hollow motor 12, the incident light scans the sample to be measured circumferentially.

[0044] The above embodiments only represent the implementation modes of the present invention, but should not be construed as limiting the scope of the patent of the present invention. It should be noted that for those skilled in the art, without departing from the concept of the present invention, several deformations and improvements can still be made, and these all belong to the protection scope of the present invention.

Claims

1. A telescopic variable-focus spinning OCT scanning probe, characterized in that: The telescopic variable-focus spinning OCT scanning probe can be axially fed while being carried on a mobile platform to achieve circumferential scanning measurement of a sample to be tested; the telescopic variable-focus spinning OCT scanning probe comprises a large outer casing (1), a small casing (9), a probe (15) and a micro hollow motor (12); the large outer casing (1) is an outermost straight casing, and a transparent casing (14) is installed at the right end, and the transparent casing (14) is a left-open and right-closed structure; the small casing (9) is placed in the large outer casing (1) and connected to the motor casing (11) for positioning, and the probe (15) is placed inside the small casing (9); The small sleeve (9) can slide smoothly and steadily with the large sleeve (1) of the outer shell; the probe (15) includes, from left to right, the following components arranged in sequence along the direction from the incident light of the optical fiber (3) to the sample to be tested: an optical fiber (3), a capillary glass tube (5), a self-focusing lens (7), and a plano-convex lens (8); the micro hollow motor (12) is placed in a motor sleeve (11); a reflective prism (13) is bonded to the right end of the micro hollow motor (12); the reflective prism (13) is deeply inserted into a transparent sleeve (14); a wire (10) is led out from the left end of the micro hollow motor (12); the wire (10) is led out and connected to an external power source.

2. The telescopic variable-focus spinning OCT scanning probe according to claim 1, characterized in that: The various components of the probe (15) are bonded together using optical glue, and the end of the probe (15) away from the sample to be tested is positioned with the small sleeve (9) through a stepped structure; The outer shell large sleeve (1) is in the shape of a straight cylinder, with smooth inner and outer surfaces without grooves. The right end surface of the outer shell large sleeve (1) is bonded with a transparent sleeve (14) using optical glue. The transparent sleeve (14) has the same inner and outer diameters as the outer shell large sleeve (1) and is coaxially aligned.

3. The telescopic variable-focus spinning OCT scanning probe according to claim 1, characterized in that: The small sleeve (9) is in the shape of a straight tube, and a through slot is formed on the outer cylindrical surface of the small sleeve (9) for leading the wire (10) out of the large sleeve (1) of the outer shell and connecting it to an external power source; a block with a bow height of 0.8 mm is cut off from the right end surface of the small sleeve (9), and the cut-off portion is coaxially aligned with the through slot to avoid interference between the right end surface of the small sleeve (9) and the wire (10) of the micro hollow motor.

4. The telescopic variable-focus spinning OCT scanning probe according to claim 1, characterized in that: The probe (15) further comprises a probe sleeve (2), a self-focusing lens sleeve (6) and a plano-convex lens sleeve (4); the probe sleeve (2) is arranged at the leftmost end of the small sleeve (9); the optical fiber (3) enters from the left side of the probe sleeve (2) and exits from the right side, and the end of the optical fiber (3) is inserted into the capillary glass tube (5); the capillary glass tube (5) and the self-focusing lens (7) are placed together in the self-focusing lens sleeve (6); the left end face of the capillary glass tube (5) is aligned with the left end face of the self-focusing lens sleeve (6), and the right end face of the capillary glass tube (5) is located in the self-focusing lens sleeve (6); the self-focusing lens (7) is spaced apart from the capillary glass tube (5), and the right end face of the self-focusing lens (7) extends out of the right end face of the self-focusing lens sleeve (6); The center of the right side of the capillary glass tube (5) is located at the focal position of the self-focusing lens (7). The light beam is emitted from the end of the optical fiber (3) and diverges, is collimated by the self-focusing lens (7), and is emitted in parallel from the right side of the self-focusing lens (7).

5. The telescopic variable-focus spinning OCT scanning probe according to claim 4, characterized in that: The left end surface of the capillary glass tube (5) is coaxially connected to the right end surface of the probe sleeve (2); The left end of the plano-convex lens sleeve (4) is inserted into the probe sleeve (2), and the right end is inserted into the plano-convex lens (8); The left side of the plano-convex lens (8) is a convex surface, and the right side is a flat surface; The right end face of the capillary glass tube (5) is tilted, and the left end face of the self-focusing lens (7) is also tilted. The left end face of the self-focusing lens (7) is parallel to the right end face of the capillary glass tube (5). The capillary glass tube (5) and the self-focusing lens (7) are spaced apart.

6. The telescopic variable-focus spinning OCT scanning probe according to claim 5, characterized in that: The inclination angle of the right end face of the capillary glass tube (5) is 8° clockwise along the radial direction perpendicular to the end face.

7. The telescopic variable-focus spinning OCT scanning probe according to claim 1, characterized in that: The micro hollow motor (12) comprises a motor body, a hollow shaft (16) and a wire (10); the right end face of the hollow shaft (16) of the micro hollow motor (12) is connected to a reflection prism (13), and the reflection prism (13) is an internal reflection prism; the reflection plane of the reflection prism (13) forms a certain angle with the axis of the micro hollow motor (12).

8. The telescopic variable-focus spinning OCT scanning probe according to claim 7, characterized in that: The angle between the reflection plane of the reflection prism (13) and the axis of the micro hollow motor (12) is in the range of 30° to 60°.

9. The telescopic variable-focus spinning OCT scanning probe according to claim 1, characterized in that: The surface of the self-focusing lens (7) has an anti-reflection film, the surface of the plano-convex lens (8) has an anti-reflection film, and the reflecting surface of the reflecting prism (13) has an anti-reflection film.

10. The telescopic variable-focus spinning OCT scanning probe according to claim 1, characterized in that: The system light source is input into an optical fiber (3), and a light beam is scattered from the end of the optical fiber (3), collimated by a self-focusing lens (7), and then incident in parallel on a plano-convex lens (8). After being focused by the plano-convex lens (8), the light beam is obliquely reflected by a reflecting prism (13), and then incident on the surface of a sample to be measured through a transparent sleeve (14). During measurement, the hollow shaft (16) of the micro hollow motor (12) rotates, driving the reflecting prism (13) to rotate, thereby realizing circumferential scanning measurement of the sample to be measured. The distance between the inner surface of the sample to be tested and the central axis of the spinning OCT scanning probe is 12 mm-18 mm; The sample to be tested is a round hole, a square hole or a cavity structure.

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