A method and device for detecting the uniformity of the coating thickness of an optical fiber

Abstract

The present application relates to the technical field of optical fiber surface coating technology, and particularly relates to a kind of optical fiber coating thickness uniformity detection method and device;Including the following steps: S1: fixed good optical fiber;S2: collect the image before optical fiber coating, obtain initial optical fiber image;S3: collect the image after optical fiber initial coating, and the coated optical fiber is rotated angle θ in turn until rotating a circle, and the optical fiber image after optical fiber rotating angle θ is collected in turn, obtain multiple coated optical fiber images;S4: the optical fiber center axis of each coated optical fiber image is compared with the optical fiber center axis of initial optical fiber image in turn, and continue coating.This application divides the coating process of optical fiber into multiple times, can detect the coating condition of optical fiber after initial coating, real-time detect the coating thickness uniformity of optical fiber surface in the coating process, according to the detection result, the optical fiber is supplemented sputtering, adjusts sputtering parameter, through multiple coating, can effectively improve the efficiency and uniformity of coating, improve product yield.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of optical fiber surface coating technology, and particularly relates to an optical fiber coating thickness uniformity detection method and device. BACKGROUND

[0002] Optical fiber is widely used in communication and sensing fields due to its small size, low cost, and immunity to electromagnetic interference. In most cases, optical fiber needs to be welded to metal for interfacing with other periods, but the weldability between the optical fiber surface coating layer and the metal is very low, and direct welding is prone to disconnection. Therefore, a layer of film needs to be plated on the surface of the optical fiber to improve its weldability with metal, and the tensile strength and sensitivity to temperature and stress of the gold-plated optical fiber are also enhanced.

[0003] The existing optical fiber surface coating methods include nanoparticle attachment, chemical deposition, thermal evaporation, and magnetron sputtering. Thermal evaporation and magnetron sputtering are the most widely used coating technologies due to their high film quality and strong repeatability. However, due to various factors, it is difficult to achieve uniform coating thickness on the surface of the optical fiber during actual coating process. The most important thing in coating the surface of the optical fiber is to control the uniformity of the coating. Non-uniform coating thickness will cause uneven stress distribution on the surface of the optical fiber, increasing the risk of coating disconnection during subsequent welding process. Therefore, there is an urgent need for an optical fiber coating thickness uniformity detection method and device to solve the problem of optical fiber coating uniformity. SUMMARY

[0004] To solve the above problems, on the one hand, the present application provides an optical fiber coating thickness uniformity detection method, which specifically includes the following steps:

[0005] S1: placing and fixing the optical fiber in the sputtering chamber, and recording the position of the optical fiber;

[0006] S2: collecting the image of the optical fiber before coating, to obtain the initial optical fiber image;

[0007] S3: after the initial coating of the optical fiber, collecting the image of the optical fiber after the initial coating, and rotating the optical fiber by an angle θ after collecting the image after the initial coating until it is rotated by 360 degrees, and collecting the optical fiber image after rotating by an angle θ, to obtain a plurality of coated optical fiber images;

[0008] S4: comparing the optical fiber center axis of each coated optical fiber image with the optical fiber center axis of the initial optical fiber image;

[0009] If the deviation is less than the preset threshold, the coating film on the fiber surface is uniform, the fiber is continuously coated, and steps S3-S4 are repeated until the set coating thickness is reached; if the deviation is greater than the preset threshold, the fiber is subjected to additional sputtering, the fiber is continuously coated, and steps S3-S4 are repeated until the set coating thickness is reached.

[0010] Further, in the step S3, the rotation angle of the fiber is 0.1-10°.

[0011] Further, in the step S4, the comparison of the fiber center axis of each coated fiber image with the fiber center axis of the initial fiber image further comprises determining the position of the fiber projected on the image by using an edge detection algorithm, and marking the position of the fiber center axis.

[0012] Further, in the step S4, the difference in coating thickness on both sides of the coated fiber image is d, the left side is positive, and the right side is negative, and the value of d obtained by continuously rotating the fiber to obtain images is accumulated to obtain D, and the uneven coating position of the fiber is determined according to D, wherein n-m>10. m to d n mn mn

[0013] Further, in the step S4, if the deviation is greater than the preset threshold, the fiber is subjected to additional sputtering, and the sputtering parameters are adjusted.

[0014] Further, the sputtering parameters include the self-rotation speed of the fiber, the sputtering material spraying speed, and the sputtering coating time.

[0015] Further, the fiber is arranged in the sputtering chamber through a fiber clamp, and the fiber clamp is connected with a motor for driving the self-rotation of the fiber.

[0016] On the other hand, the present application also provides a detection device for the fiber coating thickness uniformity detection method as described above, which comprises a sputtering cavity arranged in a sputtering chamber, and an image acquisition device, wherein the sputtering chamber is further provided with a fiber, the image acquisition device is arranged towards the fiber, and the sputtering cavity is arranged towards the fiber.

[0017] Further, the image acquisition device comprises a CCD camera.

[0018] Further, the fiber is arranged in the sputtering chamber through a fiber clamp.

[0019] The present application has the following beneficial effects compared with the prior art by adopting the above technical scheme:

[0020] ​​​The fiber coating thickness uniformity detection method and apparatus provided by this invention divides the fiber coating process into multiple operations. After the initial coating, the fiber coating condition can be detected. During the coating process, the uniformity of the coating thickness on the fiber surface can be detected in real time. Based on the detection results, the fiber can be sputtered again, and the sputtering parameters can be adjusted to improve the effect of the next sputtering coating. Through multiple coatings, the coating efficiency and uniformity can be effectively improved, thereby increasing the product yield. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the fiber optic coating thickness uniformity detection device of the present invention;

[0022] Figure 2 This is a schematic diagram of the CCD coordinate image without optical fiber in the optical fiber coating thickness uniformity detection method of the present invention.

[0023] Figure 3 This is a schematic diagram of the CCD coordinate image before fiber coating in the fiber coating thickness uniformity detection method of the present invention.

[0024] Figure 4 This is a schematic diagram of the CCD coordinate image after fiber coating in the fiber coating thickness uniformity detection method of the present invention.

[0025] Figure 5 This is a schematic diagram of the CCD coordinate image after fiber coating in the fiber coating thickness uniformity detection method of the present invention. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. In the accompanying drawings, the dimensions and relative dimensions of certain parts may be enlarged for clarity.

[0027] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connection" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two elements or the interaction between two elements. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0028] In the description of the present application, the terms "upper", "lower", "left", "right", "front", "back" and the like orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0029] In addition, in the description of the present application, the terms "first", "second" are only used to distinguish in description.

[0030] Embodiment 1

[0031] As shown in the description Figure 1 The present application provides a kind of optical fiber coating thickness uniformity detection device, including being set in sputtering chamber sputtering cavity 1, image acquisition device 2, the sputtering chamber is also provided with optical fiber 3, the image acquisition device 2 is towards the optical fiber 3 setting, the sputtering cavity 1 is towards the optical fiber 3 setting, in this embodiment, with optical fiber magnetron sputtering is elaborated in detail, sputtering cavity is towards the optical fiber setting, for sputtering process to optical fiber is coated, image acquisition device is towards the optical fiber setting, for collecting the image of optical fiber, for detecting the coating thickness uniformity of optical fiber, to adjust sputtering parameter, improve coating efficiency, make coating more uniform.

[0032] Specifically, in this embodiment, image acquisition device includes CCD camera and CCD screen, wherein, the CCD camera is set in sputtering chamber, and is towards the optical fiber setting, the CCD screen is located outside sputtering chamber, is equipped with image processing software, for processing image, CCD camera can collect the image before and after optical fiber coating, without taking down optical fiber, can detect the coating thickness uniformity of optical fiber by collecting the image after coating, and adjust sputtering parameter according to whether the optical fiber film layer is uniform, to improve the coating thickness uniformity of optical fiber. Preferably, in the process of coating, can be coated for many times, after each coating, collect the image after optical fiber coating, judge coating uniformity, adjust sputtering parameter, optimize the next optical fiber coating uniformity, can be set according to actual demand Coating times, when the film layer of the same material is sputtered, preferably twice or three times coating.

[0033] Optimized implementation, in order to make optical fiber uniform in sputtering chamber, optical fiber is set in sputtering chamber through optical fiber clamp, and optical fiber clamp is connected with motor, can drive optical fiber to rotate under the drive of motor, in the process of coating, optical fiber rotation, can make coating more uniform.

[0034] In one of the detailed embodiments, the sputtering chamber is provided with at least one sputtering cavity, wherein the material of the at least one sputtering cavity is gold, or the material of the at least one sputtering cavity is nickel, or the material of the at least one sputtering cavity is titanium, the optical fiber raw material is shielded except the coating area, the coating layer of the area to be coated is stripped before the optical fiber is coated, the cladding is exposed for coating, the optical fiber raw material is placed in the chamber of the magnetron sputtering coating machine, a plurality of sputtering cavities are preloaded in the chamber, the air in the sputtering chamber is extracted by a vacuum pump, when the vacuum degree in the sputtering chamber reaches a preset value, the film layer sputtering is started, that is, the sputtering cavity raw material in the sputtering chamber is sputtered to the coating area of the optical fiber raw material. In the present application, the sputtering cavity in the sputtering chamber at least includes a gold target, or at least includes a nickel target, or at least includes a titanium target. Specifically, the sputtering chamber has a plurality of target materials, which can be a combination of gold targets, nickel targets and silicon dioxide targets, a combination of gold targets, nickel targets and chromium targets, or a combination of platinum targets, nickel targets and titanium targets. In short, at least one is a gold target or a nickel target or a titanium target to ensure the quality of the sputtered film. During the coating process, the sputtering cavities of different materials can be started in sequence to make the different target materials sputter on the optical fiber cladding in different time periods.

[0035] Example 2

[0036] The present application also provides a method for detecting the uniformity of the coating thickness of an optical fiber, which specifically comprises the following steps:

[0037] S1: placing and fixing the optical fiber in the sputtering chamber and recording the position of the optical fiber;

[0038] Specifically, before sputtering, the sputtering cavity is removed, the optical fiber is placed and fixed, and the motor for driving the optical fiber to rotate is in the initial position.

[0039] S2: collecting the image of the optical fiber before coating to obtain an initial optical fiber image;

[0040] S3: after the optical fiber is coated for the first time, the image of the optical fiber after the first coating is collected, and the optical fiber after the first coating is rotated by an angle θ in sequence until it is rotated by 360 degrees, and the optical fiber image after the optical fiber is rotated by an angle θ is collected in sequence to obtain a plurality of coated optical fiber images. Specifically, the rotation angle θ of the optical fiber is 0.1-10°. The smaller the rotation angle, the more accurate it is, and a large amount of data needs to be processed. The appropriate rotation angle is selected according to the actual demand for debugging.

[0041] S4: comparing the central axis of the optical fiber of each coated optical fiber image with the central axis of the initial optical fiber image in sequence;

[0042] If the deviation is less than the preset threshold, the fiber surface coating is uniform, the fiber is continuously coated, and steps S3-S4 are repeated until the set coating thickness is reached; if the deviation is greater than the preset threshold, the fiber is supplemented with sputtering, the fiber is continuously coated, and steps S3-S4 are repeated until the set coating thickness is reached.

[0043] Specifically, in the above coating process, it can be necessary to sequentially coat different materials on the fiber, such as an inner film layer, a middle film layer, or an outer film layer. For the same film layer, the coating process can be divided into two or three times of coating. For example, the thickness of the inner film layer is h, and the average coating thickness is 1 / 3h-1 / 2h during the first coating. After the first coating is completed, the fiber coating image is collected, and it is determined whether the fiber coating thickness is uniform. If it is uniform, the existing sputtering parameters are used for coating until the average thickness of the inner film layer is h. If the fiber coating image is collected after the first coating, it is determined that the fiber coating thickness is not uniform, the fiber is supplemented with sputtering, and the sputtering parameters are adjusted according to the requirements, and the fiber is continuously coated until the average thickness of the inner film layer is h.

[0044] In order to make the coating more uniform, the fiber is arranged in the sputtering chamber through a fiber clamp, and a motor for driving the fiber to rotate is connected to the fiber clamp. Through image acquisition, the fiber surface coating thickness uniformity problem can be detected in real time during the coating process, and the sputtering parameters, including the fiber rotation speed, the sputtering material spraying speed, and the sputtering coating time, are adjusted through multiple coatings, to improve the subsequent coating effect and improve the efficiency and uniformity of the coating.

[0045] The following is a detailed description of a specific embodiment:

[0046] 1. Before sputtering, remove the sputtering chamber, fix the fiber, and place the motor at the initial position. Store the pre-coating fiber image captured by the CCD camera as P0.

[0047] 2. Start the motor to make the fiber start to rotate, move the sputtering chamber back and align the fiber for coating;

[0048] 3. After a period of time t, the first coating is completed, the coating is stopped, the sputtering chamber is removed, the motor is controlled to stop the fiber from rotating, the post-coating fiber image captured by the CCD camera is stored as P1, and the position of the fiber at this time is recorded as the initial position.

[0049] 4. Rotate the fiber 10° clockwise or counterclockwise from the initial position, use the CCD camera to capture the image again, and store the image as P2.

[0050] 5. Continue rotating the optical fiber in the same direction by 10° increments until it completes one full rotation. Use a CCD camera to capture images P representing each full rotation of the optical fiber at 10° intervals. i The value of i is 3, 4, 5...37, corresponding to rotation angles of 2*θ, 3*θ...36*θ, where θ = 10°;

[0051] 6. Use an edge detection algorithm to determine the position of the fiber projection on the CCD coordinate axis, and mark the position of the fiber's central axis, as shown in the instruction manual. Figure 2 The image shown is a CCD coordinate axis image without optical fiber, as per the instruction manual. Figure 3 The image shown is an image of the optical fiber on the CCD coordinate axis before coating, as per the instruction manual. Figure 3 The image shown is an image of the optical fiber on a CCD coordinate axis after coating. For a (m+1)×(n+1) CCD coordinate image, the central axis of the optical fiber before coating is the initial central axis, which is located at column (n / 2+1) of the image. The optical fiber rotates during the coating process to ensure that the initial central axis does not shift in the horizontal direction. After coating, the central axis of the optical fiber after coating is the coating central axis. Several images are acquired during the rotation of the optical fiber, and each image corresponds to a coating central axis.

[0052] 7. Set the deviation threshold of the coating center axis as δ, and the preset fiber coating thickness as h. Then, the deviation threshold δ of the fiber center axis should be ≤0.05h. The value of δ is set according to actual needs, usually not exceeding 0.2μm. Compare the coating center axis of each coated fiber image with the initial center axis of the initial fiber image to determine whether the coating thickness on the fiber surface is uniform. If the coated fiber image P... j The coating center axes corresponding to (j≤i) are all located between (n / 2+1-δ, n / 2+1+δ), meaning the deviation is less than the preset threshold. Therefore, the coating thickness on the fiber surface is considered uniform. Continue with P... j+1 Compared with P0, if P j+1 If the coating center axis of the corresponding fiber projection is partially or entirely located at (1, n / 2 + 1 - δ), the coating on the left side of the fiber is considered to be thicker. If the coating center axis of the corresponding fiber projection is partially or entirely located at (n / 2 + 1 + δ, n), the coating on the right side of the fiber is considered to be thicker. (See attached manual.) Figure 4 The image shown is a CCD image of a fiber with uniform coating on both sides, as per the instruction manual. Figure 5 The image shown is a CCD image when the coating on the left side of the optical fiber is too thick; for cases where the coating is too thin, local sputtering can be performed on the optical fiber.

[0053] 8. Denote the difference in coating thickness between the two sides of the coated fiber image as d. i Thicker fibers on the left are considered positive, and thicker fibers on the right are considered negative. Images of coated optical fibers with continuous rotation angles are selected, and the values ​​for d are summed. For example, d...m to d n The cumulative value of d mn (n-m>10), when the absolute value |D mn of d mn has a maximum value, it is considered that the optical fiber is in the image P m to P n The overall coating thickness uniformity in the range of the corresponding rotation angle (m-1)*theta, (n-1)*theta, and according to the positive and negative of d mn judges whether the optical fiber is left or right thickness non-uniform, and the optical fiber area on the thin side of the rotation angle (m-1)*theta, (n-1)*theta of the optical fiber is supplemented with sputtering.

[0054] 9. After the first coating described above, adjust the sputtering parameters, such as adjusting the optical fiber rotation speed, sputtering material spraying speed and sputtering coating time, optimize the sputtering parameters, and repeat the above operation to perform the second and third coating until the coating thickness reaches the set value.

[0055] In summary, the present application provides a kind of optical fiber coating thickness uniformity detection method and device, set sputtering cavity and image acquisition device in sputtering chamber, can real-time detect optical fiber surface coating thickness uniformity during coating process, so as to adjust sputtering parameters in time, and through multiple sputtering, through the sputtering situation of last time, optimize the sputtering parameters of next time, improve the efficiency and uniformity of coating.

[0056] Those skilled in the art should understand that the present application can be implemented in many other specific forms without departing from the spirit and scope of the present application. Although embodiments of the present application have been described, it should be understood that the present application should not be limited to this embodiment, and those skilled in the art can make changes and modifications within the spirit and scope of the present application as defined in the appended claims.

Claims

1. A method for detecting the uniformity of optical fiber coating thickness, characterized in that, Specifically, the steps include the following: S1: Place and fix the optical fiber in the sputtering chamber, and record the position of the optical fiber; S2: Acquire an image of the optical fiber before coating to obtain the initial optical fiber image; S3: After the optical fiber undergoes its first coating, an image of the optical fiber after the first coating is acquired. The optical fiber from which the image of the first coating is acquired is rotated by an angle θ until it completes one full rotation. The optical fiber image after the rotation angle θ is acquired sequentially to obtain multiple coated optical fiber images. S4: Compare the fiber center axis of each coated fiber image with the fiber center axis of the initial fiber image in turn; If all deviations are less than the preset threshold, the fiber surface coating is uniform. Continue coating the fiber and repeat steps S3-S4 until the set coating thickness is reached. If at least one of the deviations is greater than the preset threshold, perform additional sputtering on the thinner area of ​​the fiber film, continue coating the fiber and repeat steps S3-S4 until the set coating thickness is reached.

2. The method for detecting the uniformity of optical fiber coating thickness according to claim 1, characterized in that, In step S3, the optical fiber rotation angle θ is 0.1~10°.

3. The method for detecting the uniformity of optical fiber coating thickness according to claim 1, characterized in that, In step S4, comparing the fiber center axis of each coated fiber image with the fiber center axis of the initial fiber image in sequence also includes using an edge detection algorithm to determine the position of the fiber projection on the image and marking the position of the fiber center axis.

4. The method for detecting the uniformity of optical fiber coating thickness according to claim 1, characterized in that, In step S4, the difference in coating thickness between the two sides of the coated fiber image is d, with the left side being thicker and the right side being thicker and having a negative value. The d value is obtained by continuously rotating the fiber to acquire the image. m to d n The values ​​are summed to obtain D. mn And according to D mn Determine the location of uneven coating on the optical fiber, where nm > 10.

5. The method for detecting the uniformity of optical fiber coating thickness according to claim 1, characterized in that, In step S4, if the deviation is greater than a preset threshold, after supplementing sputtering on the optical fiber, the sputtering parameters are also adjusted.

6. The method for detecting the uniformity of optical fiber coating thickness according to claim 5, characterized in that, The sputtering parameters include fiber propagation speed, sputtering spray speed, and sputtering coating time.

7. The method for detecting the uniformity of optical coating thickness according to claim 1, characterized in that, The optical fiber is mounted in the sputtering chamber via an optical fiber clamp, which is connected to a motor for driving the optical fiber to rotate.

8. A detection device for the fiber optic coating thickness uniformity detection method as described in any one of claims 1-7, characterized in that, It includes a sputtering cavity and an image acquisition device disposed within a sputtering chamber. An optical fiber is also disposed within the sputtering chamber, with the image acquisition device facing the optical fiber and the sputtering cavity facing the optical fiber.

9. The optical fiber coating thickness uniformity detection device according to claim 8, characterized in that, The image acquisition device includes a CCD camera.

10. The optical fiber coating thickness uniformity detection device according to claim 8, characterized in that, The optical fiber is rotatably mounted in the sputtering chamber via an optical fiber clamp.

Images