A telescopic zoom OCT scanning probe

Abstract

The present invention belongs to the technical field of industrial surface imaging, and provides a telescopic zoom OCT scanning probe, which includes an outer shell large sleeve, a telescopic small sleeve and a probe. The outer shell large sleeve is the outermost straight tube sleeve; the telescopic small sleeve is placed in the outer shell large sleeve, and a probe is placed inside it. The probe includes, in order along the optical fiber from the direction of light incidence to the sample to be measured: a capillary glass tube, a self-focusing lens, and a plano-convex lens. The probe part is bonded with optical glue. There is also a reflection prism on the right side of the outer shell large sleeve, which is placed in a reflection prism fixing member. By controlling the relative distance between the telescopic small sleeve and the reflection prism, and adjusting the distance between the focused beam and the axis of the scanning probe, the working size of the scanning probe can be adjusted quickly and accurately; by introducing a telescopic zoom structure, the scanning probe can measure deep holes of multiple sizes, improving the measurement efficiency and measurement ability.

Description

Technical Field

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

[0002] Optical Coherence Tomography (OCT) is based on the Michelson interference 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, on which a plane mirror is installed, and the beam returns along the original path after being reflected by the mirror. The other beam is directed to the sample arm, on which the sample to be measured is placed, and the beam returns along the original path after being reflected by the sample. The two returned beams interfere, 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 diverging from the optical fiber, and to 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 an optical fiber for transmitting the optical signal and a lens for collimating and converging are built-in. Existing probes usually consist of a fixed-focus lens and a simple outer shell, and cannot adapt to measuring deep holes of different sizes. Measuring outside the focal length of the probe will greatly reduce the imaging quality.

[0004] Some endoscope measurement methods based on OCT technology have been proposed, such as:

[0005] In an OCT probe proposed in Chinese invention patent ZL 202111015041.4, a self-focusing lens is used to converge the light beam emitted from the optical fiber. Based on the characteristics of the self-focusing lens itself, this probe faces the problems of small working distance and limited focal depth, and can only measure the lumen structure of a fixed size.

[0006] In an OCT probe proposed in Chinese invention patent ZL 201610678116.X, a self-focusing optical fiber is fused to the end of a single-mode optical fiber, and then the end of the self-focusing optical fiber is sintered into a spherical lens to converge the light beam. It also faces the problem of fixed working distance and can only measure the lumen structure of a fixed size.

[0007] In a large focal depth OCT probe proposed in Chinese invention patent ZL 202311065279.7, a double-lens structure is formed by the spherical lens at the end of the optical fiber and the cylindrical lens located at the imaging window. At a medium working distance, the lateral resolution and focal depth of the probe are effectively improved. However, at a smaller or larger distance, the probe also needs to be replaced, which affects the measurement efficiency. Summary of the Invention

[0008] In order to overcome the deficiencies of the prior art, the present invention provides a telescopic variable-focus scanning probe. By controlling the distance between the plano-convex lens (focusing lens) and the reflecting prism, the distance between the focus and the axis of the probe is changed, so as to control the measuring distance and measure holes with different diameter sizes.

[0009] The technical solutions adopted to solve the technical problems proposed by the present invention are as follows:

[0010] A telescopic variable-focus OCT scanning probe, the telescopic variable-focus OCT scanning probe includes an outer shell large sleeve 1, a telescopic small sleeve 9 and a probe 13. The outer shell large sleeve 1 is the outermost straight cylindrical sleeve; the telescopic small sleeve 9 extends into the outer shell large sleeve 1 from the left side of the outer shell large sleeve 1, and a probe 13 is placed inside the telescopic small sleeve 9. The probe includes, in order from the light incident on the fiber to the direction of the sample to be measured (from left to right): an optical fiber 3, a capillary glass tube 5, a self-focusing lens 7, and a plano-convex lens 8. There is a gap between the self-focusing lens 7 and the plano-convex lens 8, and each part is bonded with optical glue. A reflecting prism 10 is provided on the right side of the outer shell large sleeve 1, and the end of the outer shell large sleeve is sealed by a sleeve cover 12.

[0011] Furthermore, the outer shell large sleeve 1 is in a straight cylindrical shape, with smooth inner and outer surfaces without grooves. At a certain distance from the end face where the sleeve cover 12 is located inside the outer shell large sleeve 1, there is also a light passing hole, and the diameter of the light passing hole is larger than the beam diameter.

[0012] Furthermore, the telescopic small sleeve 9 is placed inside the outer shell large sleeve 1, and the two can slide smoothly and smoothly, and the sliding distance is the same as the variable-focus distance. The sliding distance is the relative sliding distance of the telescopic small sleeve 9 inside the outer shell large sleeve 1; since the reflecting prism 10 obliquely reflects the focused beam, the beam focus is no longer located at the axis position of the scanning probe. The variable-focus distance is the changing distance between the beam focus and the axis of the scanning probe. When the telescopic small sleeve 9 slides a certain distance in the direction approaching the reflecting prism 10, the beam focus correspondingly moves the same distance further away from the axis of the scanning probe; when the telescopic small sleeve 9 slides a certain distance in the direction away from the reflecting prism 10, the beam focus correspondingly moves the same distance closer to the axis of the scanning probe.

[0013] Furthermore, the probe includes a probe sleeve, an optical fiber, a capillary glass tube, a self-focusing lens, a plano-convex lens, a self-focusing lens sleeve and a plano-convex lens sleeve. Specifically:

[0014] The probe 13 is placed inside the telescopic small sleeve 9 through the probe sleeve 2.

[0015] The capillary glass tube 5 and the self-focusing lens 7 are jointly placed inside the self-focusing lens sleeve 6, and the self-focusing lens 7 and the capillary glass tube 5 are placed at intervals.

[0016] The plano-convex lens 8 is placed inside the telescopic small sleeve 9 through the plano-convex lens sleeve 4. The outer surface of the plano-convex lens sleeve 4 fits with the inner surface of the telescopic small sleeve 9 and fits with the outer surface of the probe sleeve 2. That is, 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.

[0017] The reflection prism 10 is placed at the right end of the outer casing large sleeve through the reflection prism fixing member 11.

[0018] Furthermore, the optical fiber 3 penetrates into the probe sleeve 2 from the left side and penetrates out from the right side; the end of the optical fiber 3 is inserted into the capillary glass tube 5.

[0019] Furthermore, the left end face of the capillary glass tube 5 is aligned with the left end face of the self-focusing lens sleeve 6.

[0020] Furthermore, the left end face of the capillary glass tube 5 is coaxially bonded to the right end face of the probe sleeve 2.

[0021] Furthermore, the side of the plano-convex lens 8 opposite to the self-focusing lens 7 (i.e., the left side) is a convex surface, and the other side (the right side) is a flat surface.

[0022] Furthermore, the right end face of the capillary glass tube 5 along the radial direction is inclined clockwise by 8°, the left end face of the self-focusing lens 7 along the radial direction is inclined clockwise by 8°, and the right end face of the capillary glass tube is parallel to the left end face of the self-focusing lens.

[0023] Furthermore, 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.

[0024] Furthermore, the reflection prism 10 is integrally cylindrical, and the left reflection plane forms a certain angle with the axis of the outer casing large sleeve 1, and the angle range is between 30° and 60°.

[0025] Furthermore, the sleeve cover 12 provided on the right side of the reflection prism fits the inner diameter of the outer casing large sleeve 1, and the right end face of the sleeve cover 12 is flush with the right end face of the outer casing large sleeve 1.

[0026] Furthermore, an antireflection film is provided on the surface of the self-focusing lens 7 and the surface of the plano-convex lens 8; an antireflection film is provided on the reflection surface of the reflection prism 10.

[0027] The system light source inputs into the optical fiber 3, then diverges and emits from the end of the optical fiber 3, and is collimated by the self-focusing lens 7. After collimation, the light beam enters the plano-convex lens 8 parallelly, and then the plano-convex lens 8 converges the light beam to achieve focusing. It is obliquely reflected by the reflection prism 10 and incident on the surface of the sample. The sample is usually a round hole, a square hole or a cavity structure, and the distance between its inner surface and the axis of the scanning probe is between 5-20 mm. The principle of variable focal length of the probe is as follows: The converging light beam with a certain focal length is obtained by converging the light by the plano-convex lens 8. After the reflection prism 10 obliquely reflects the converging light beam, the focus of the converging light beam is located on the side of the scanning probe. When the converging light beam is reflected from different cross-sections, the distance between the reflected focus and the axis of the scanning probe is different. Specifically, when the telescopic small sleeve 9 slides a certain distance in the direction close to the reflection prism 10, the light beam focus correspondingly moves the same distance further away from the axis of the scanning probe. When the light beam focus is far away, holes with larger sizes can be measured; when the telescopic small sleeve 9 slides a certain distance in the direction away from the reflection prism 10, the light beam focus correspondingly moves the same distance closer to the axis of the scanning probe. When the light beam focus is close, holes with smaller sizes can be measured. When using the scanning probe, place it at the center position of the sample (round hole, square hole or cavity structure), and adjust the distance between the telescopic small sleeve 9 and the reflection prism 10 according to the sample size until the light beam focus falls on the surface of the sample, then the measurement can be carried out.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0029] By controlling the relative distance between the telescopic small sleeve 9 and the reflection prism 10, the present invention can adjust the distance between the focused light beam and the axis of the scanning probe, so as to quickly and accurately adjust the working size of the scanning probe. In summary, the present invention introduces a telescopic variable focal length structure, enabling the scanning probe to measure deep holes of multiple sizes, improving the measurement efficiency and measurement ability. Description of the Drawings

[0030] Figure 1 It is a basic structure diagram of a telescopic variable focal length OCT scanning probe;

[0031] Figure 2 It is a schematic diagram of the telescopic variable focal length principle;

[0032] Figure 3 It is a basic structure diagram of the probe;

[0033] Figure 4 It is an optical path diagram of a telescopic variable focal length OCT scanning probe for measuring small holes;

[0034] Figure 5 It is an optical path diagram of a telescopic variable focal length OCT scanning probe for measuring large holes;

[0035] 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 telescopic small sleeve; 10 reflecting prism; 11 reflecting prism fixing member; 12 sleeve lid; 13 probe. Specific embodiments

[0036] The following further describes the structure of the invention in conjunction with the accompanying drawings and the preferred specific embodiments of the present invention. It should be noted that on the premise of no conflict, the following described embodiments or technical features can be arbitrarily combined to form new embodiments.

[0037] As Figure 1 shown, the present invention provides a telescopic zoom OCT scanning probe, and the scanning probe includes an outer shell large sleeve 1, a telescopic small sleeve 9 and a probe 13. The outer shell large sleeve 1 is the outermost sleeve, which is used to extend into a deep hole and protect the internal probe 13; the telescopic small sleeve 9 is used to smoothly and stably move within the outer shell large sleeve 1 to adjust the distance between its built-in probe 13 and the reflecting prism. The probe 13 includes, in the order of light incident from the optical fiber 3 to the direction of the sample to be measured (from left to right): the optical fiber 3, the capillary glass tube 5, the self-focusing lens 7, and the plano-convex lens 8. There is a gap between the self-focusing lens 7 and the plano-convex lens 8, and each part is bonded with optical glue.

[0038] Preferably, the outer shell large sleeve 1 is in a straight cylindrical shape, and its inner and outer surfaces are smooth without grooves. At a certain distance from the end face where the sleeve lid 12 is located inside the outer shell large sleeve 1, there is also a light passing hole, and the diameter of the light passing hole is larger than the beam diameter. The telescopic small sleeve 9 is in a straight cylindrical shape. When it is placed inside the outer shell large sleeve 1, the two can slide smoothly and stably, and the sliding distance is the same as the zoom distance. The sliding distance is the relative sliding distance of the telescopic small sleeve 9 inside the outer shell large sleeve 1, and the zoom distance is the changing distance between the beam focus and the axis of the probe 13. When the telescopic small sleeve 9 slides towards the reflecting prism 10, the beam focus correspondingly moves the same distance further away from the axis of the probe 13. Conversely, the beam focus correspondingly moves the same distance closer to the axis of the probe 13. As Figure 2 shown, driving the probe 13 to slide a certain distance towards the reflecting prism 10, the beam focus correspondingly moves the same distance further away from the axis of the probe 13. When the beam focus is far away, larger-sized holes can be measured. Conversely, the beam focus correspondingly moves the same distance closer to the axis of the probe 13. When the beam focus is close, smaller-sized holes can be measured.

[0039] Furthermore, as Figure 3As shown, the probe 13 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 3 penetrates into the probe sleeve 2 from the left side and exits from the right side. The end of the optical fiber 3 is inserted into the capillary glass tube 5. The left end face of the self-focusing lens 7 is aligned with the left end face of the self-focusing lens sleeve 6.

[0040] Preferably, the gradient constant of the self-focusing lens 7 is 1.37, the central refractive index is 1.616, and the thickness is 5.6 mm; the focal length of the plano-convex lens is 20 mm, and the diameter is 2.3 mm; the distance between the capillary glass tube 5 and the self-focusing lens 7 is 3 mm.

[0041] Preferably, 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 side of the plano-convex lens 8 opposite to the self-focusing lens 7 (i.e., the left side) is convex, and the other side is flat. The right end face of the capillary glass tube 5 is inclined clockwise by 8°, and the left end face of the self-focusing lens 7 is inclined clockwise by 8°. 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] Furthermore, the reflection prism 10 is placed in the reflection prism fixing member 11. The reflection prism 10 is generally cylindrical. The left reflection plane forms a certain angle with the axis of the outer shell large sleeve 1, and the angle range is between 30° and 60°. A sleeve cover 12 is provided on the right side of the reflection prism 10, which fits the inner diameter of the outer shell large sleeve 1. The right end face of the sleeve cover 12 is flush with the right end face of the outer shell large sleeve 1.

[0043] Preferably, an anti-reflection film is provided on the surfaces of the self-focusing lens 7 and the plano-convex lens 8; an anti-reflection film is provided on the reflection surface of the reflection prism 10.

[0044] In the present invention, the system light source is input into the optical fiber 3, then diverges and emits 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 plano-convex lens 8 converges the light beam to achieve focusing. The light beam is obliquely reflected by the reflection prism 10 and incident on the surface of the sample. The sample is usually a round hole, a square hole or a deep cavity structure, and the distance between its inner surface and the axis of the scanning probe is between 5-20 mm. The principle of variable focal length of the probe is as follows: the plano-convex lens 8 converges the light rays to obtain a converging light beam with a certain focal length. After the reflection prism 10 obliquely reflects the converging light beam, the focus of the converging light beam is located on the side of the scanning probe. When the converging light beam is reflected from different cross-sections, the distance between the reflected focus and the axis of the scanning probe is different. Specifically, when the telescopic small sleeve 9 slides closer to the reflection prism 10, the focus of the light beam correspondingly moves the same distance further away from the axis of the probe 13. When the focus of the light beam is far away, holes with larger sizes can be measured; when the telescopic small sleeve 9 slides away from the reflection prism 10, the focus of the light beam correspondingly moves the same distance closer to the axis of the probe 13. When the focus of the light beam is close, holes with smaller sizes can be measured. When using the scanning probe, place it at the center position of the sample (round hole, square hole or deep cavity structure), and adjust the distance between the telescopic small sleeve 9 and the reflection prism 10 according to the size of the sample until the focus of the light beam falls on the surface of the sample, then the measurement can be carried out.

[0045] In the present invention, by controlling the relative distance between the telescopic small sleeve 9 and the reflection prism 10, the distance between the focused light beam and the axis of the scanning probe can be adjusted to quickly and accurately adjust the working size of the scanning probe. In summary, the present invention introduces a telescopic variable focal length structure, enabling the scanning probe to measure deep holes of multiple sizes, improving the measurement efficiency and measurement ability.

[0046] The above embodiments only represent the implementation modes of the present invention, but should not be construed as limiting the scope of the present invention patent. 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 OCT scanning probe, characterized in that: The telescopic variable-focus OCT scanning probe comprises a large outer casing (1), a telescopic small casing (9) and a probe (13); the large outer casing (1) is an outermost straight casing; the telescopic small casing (9) penetrates into the large outer casing (1) from the left side of the large outer casing (1), and the probe (13) is placed inside the telescopic small casing (9); the probe comprises an optical fiber (3), a capillary glass tube (5), a self-focusing lens (7), and a plano-convex lens (8) arranged in sequence along the direction from the incident light of the optical fiber to the sample to be tested; a reflecting prism (10) is provided on the right side of the large outer casing (1); The probe (13) comprises 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); specifically: The probe (13) is placed in the telescopic small sleeve (9) through the probe sleeve (2); The capillary glass tube (5) and the self-focusing lens (7) are placed together in the self-focusing lens sleeve (6), and the self-focusing lens (7) and the capillary glass tube (5) are placed at intervals; The optical fiber (3) enters from the left side of the probe sleeve (2) and exits from the right side, and its end is inserted into the capillary glass tube (5); The plano-convex lens (8) is placed in the telescopic small sleeve (9) through the plano-convex lens sleeve (4), wherein the outer surface of the plano-convex lens sleeve (4) is in contact with the inner surface of the telescopic small sleeve (9) and the outer surface of the probe sleeve (2), that is, 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 reflecting prism (10) is placed at the right end of the large casing (1) of the housing via a reflecting prism fixing member (11); The telescopic small sleeve (9) is placed inside the large sleeve (1) of the housing, and the two can slide smoothly, and the sliding distance is the same as the zoom distance; when the telescopic small sleeve (9) slides a certain distance away from the reflective prism (10), the focus of the light beam moves the same distance closer to the axis of the scanning probe accordingly; The plano-convex lens (8) has a convex surface on one side opposite to the self-focusing lens (7), and a flat surface on the other side; The center of the right side of the capillary glass tube (5) is located at the focal position of the self-focusing lens (7), and 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); The right side end face of the capillary glass tube (5) along the radial direction is inclined 8° clockwise, the left side end face of the self-focusing lens (7) along the radial direction is inclined 8° clockwise, and the right side end face of the capillary glass tube is parallel to the left side end face of the self-focusing lens.

2. The telescopic variable-focus OCT scanning probe according to claim 1, characterized in that: A gap is left between the self-focusing lens (7) and the plano-convex lens (8), and the various parts are bonded together using optical glue; the end of the large casing (1) of the outer shell is sealed by a casing cover (12).

3. The telescopic variable-focus OCT scanning probe according to claim 1, characterized in that: The outer shell large sleeve (1) is in the shape of a straight cylinder, with smooth inner and outer surfaces without grooves. There is also a light hole inside the outer shell large sleeve (1) at a certain distance from the end face where the sleeve cover (12) is located, and the diameter of the light hole is larger than the diameter of the light beam.

4. The telescopic variable-focus OCT scanning probe according to claim 1, characterized in that: The left end surface of the capillary glass tube (5) is aligned with the left end surface of the self-focusing lens sleeve (6); and the left end surface of the capillary glass tube (5) is coaxially bonded to the right end surface of the probe sleeve (2).

5. The telescopic variable-focus OCT scanning probe according to claim 1, characterized in that: The reflecting prism (10) is cylindrical as a whole, and the left reflecting plane forms a certain angle with the axis of the large casing (1) of the outer shell.

6. The telescopic variable-focus OCT scanning probe according to claim 5, characterized in that: The angle range is between 30° and 60°.

7. The telescopic variable-focus OCT scanning probe according to claim 1, characterized in that: The surface of the self-focusing lens (7) and the surface of the plano-convex lens (8) are provided with anti-reflection films; and the reflecting surface of the reflecting prism (10) is provided with an anti-reflection film.

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