Optical detection device and cleaning detection apparatus for a deep cavity fiber end face

Abstract

The application provides an optical detection device for a deep-cavity optical fiber end face and a cleaning detection equipment, and belongs to the field of optical communication. The optical detection device comprises a light source barrel lens, an illumination turning unit, an imaging turning unit, a telescope lens group, a detection prism, an imaging barrel lens, an imaging unit and a focusing unit. The imaging turning unit is used for turning the image and expanding the space. The telescope lens group realizes long-distance image transmission in a narrow space. After the oblique outgoing illumination light of the detection prism is deflected, it is perpendicular to the surface to be detected, and the illumination is more uniform. The imaging barrel lens adopts an image-side telecentric design. The imaging unit adopts a no-interface Schmitt structure design, which can solve the shallow depth of field problem caused by high resolution and realize automatic focusing with the focusing unit. The overall structure of the application is simple and stable in imaging. The front-end integrated prism turning light path eliminates the perspective error, and the double light path design improves the detection efficiency. The application can be widely applied in the fields of optical communication, 3C, semiconductor and the like with deep-cavity scenes.

Description

Technical Field

[0001] This invention belongs to the field of optical communication, specifically relating to an optical inspection device and a cleaning inspection equipment for the end face of a deep cavity optical fiber. Background Technology

[0002] In the field of optical communication, the quality of the fiber endface directly affects the transmission efficiency of optical signals. For optical modules containing panda-type polarization-maintaining fibers, the core indicators for endface inspection typically include: the cleanliness and surface defects of the endface, the relative position of the fiber core and the stress zone (panda eyes), and the azimuth alignment. Accurately obtaining this information is a prerequisite for ensuring product performance and reliability.

[0003] See Figure 1 The optical fiber tip of the optical module is inserted into one end of the deep cavity A of the guide housing. For products with optical fiber end faces at the bottom of the deep cavity, due to the cavity's depth and narrow cross-section, the testing equipment can only approach the end face to be tested at the bottom of the cavity from the cavity opening by probing with its front end. More importantly, this end face is not perpendicular to the cavity axis, but is an angled slope. This angle fundamentally changes the optical path conditions for illumination and imaging, causing conventional testing methods to face the following prominent problems.

[0004] Conventional built-in coaxial illumination requires the object plane to be approximately perpendicular to the optical axis; otherwise, the illumination light will deviate from the collection path after reflection by the inclined plane, making it difficult to form bright-field illumination. To solve this problem, existing solutions integrate a reflector at the front end to change the direction of the illumination light path, making it approximately normally incident on the inclined plane. However, this structure introduces a series of irreconcilable contradictions, as follows.

[0005] Firstly, the introduction of a reflector forces the working distance of the lens to increase further, severely limiting the object-side numerical aperture (NA) and resulting in insufficient system resolution. Furthermore, the diameter of a single polarization-maintaining fiber on the fiber end face of the product is only about 125µm, and the stress zone (panda eye) features inside are even smaller, making it impossible for low NA systems to clearly distinguish these critical details.

[0006] Secondly, the overall size of the end face is large, and the slope has a significant height difference along its short side, resulting in a very shallow effective depth of field for the system, making it difficult to achieve a clear overall image of the entire end face in a single imaging operation. Existing single-optical-path solutions are limited by the short-side field of view of the slope, and in particular, cannot solve the problem of detectability across the entire slope area.

[0007] Third, the front-end integrated reflector not only occupies the already limited field of view, further reducing the effective field of view, but also, because it is located near the illumination and imaging optical path, introduces ghost images of the reflector into the final image, interfering with the judgment of the true defects of the end face.

[0008] Fourth, the existing technology uses a single-tube relay mirror structure, which can only complete the inspection of one product end face at a time. When there are two modules to be tested at the bottom of the cavity, they must be inspected one by one by moving the inspection equipment, resulting in low inspection efficiency.

[0009] In summary, existing technologies for detecting the inclined fiber end face within deep cavities have significant shortcomings in terms of resolution, field of view coverage, imaging quality, and detection efficiency, and a new detection scheme that can overcome these problems is urgently needed. Summary of the Invention

[0010] In order to overcome the shortcomings of the prior art, the purpose of this invention is to provide an optical inspection device and a cleaning inspection equipment for the end face of a deep cavity fiber, which can solve the above-mentioned problems.

[0011] An optical detection device for the end face of a deep cavity fiber includes a teleconverter group, an imaging deflection unit, and multiple imaging units arranged sequentially from front to back; the imaging deflection unit is used to deflect the image transmission and expand the space, and the number of expanded optical paths matches the number of imaging units behind; the teleconverter group adopts a telecentric optical path for long-distance image transmission in narrow spaces.

[0012] Furthermore, the imaging deflection unit is located at the rear end of the teleconverter group, and the direction of the extended optical path is deflected from the rear end of the teleconverter group to the outer periphery.

[0013] Furthermore, the teleconverter group employs a multi-segment relay lens group to extend the detection optical path.

[0014] Furthermore, multiple imaging units designed based on Scham's law are positioned non-connected behind the imaging transition unit.

[0015] Furthermore, the imaging unit is designed without interfaces and is positioned behind the light path deflected by the imaging deflection unit in a non-contact manner, with the imaging unit arranged at an angle relative to the imaging deflection unit.

[0016] Furthermore, a detection prism is set at the front end of the teleconverter assembly. After being deflected by the oblique light path of the detection prism, the light is perpendicularly irradiated onto the end face to be measured, realizing the object-side off-axis telecentric design.

[0017] Furthermore, an imaging tube lens with the same number of imaging units is set at the rear end of the imaging turning unit. The imaging tube lens adopts an image-side telecentric design to eliminate image-side perspective error.

[0018] Furthermore, the optical detection device at the end face of the deep cavity fiber also includes an external light source, a light source tube lens, and an illumination deflection unit. The external light source forms coaxial light through the light source tube lens, and the illumination deflection unit is used to deflect the illumination beam into the teleconverter group.

[0019] Furthermore, a positioning unit is set at the front end of the teleconverter assembly. The positioning unit includes an overall positioning part and a test surface positioning part set on the positioning body. The test surface positioning part is located in front of the outer periphery of the detection prism to position the test surface. The positioning surface of the overall positioning part is located in front of the positioning surface positioning part to position the entire test product.

[0020] Furthermore, the optical detection device at the end face of the deep cavity fiber also includes a focusing unit, which includes a camera mount, a focusing slide, a focusing driver, and a detection housing. The camera mount is connected to the imaging unit, the fixing part of the focusing slide and the focusing driver are connected to the inner side of the detection housing, and the focusing driver drives the imaging unit at the camera mount to move to achieve focusing.

[0021] The present invention also provides a cleaning and testing device for the end face of a deep cavity fiber optic cable, comprising a cleaning and testing station and a product positioning platform; the cleaning and testing station includes a self-focusing optical testing device, a non-contact cleaning device, a contact cleaning device, a testing area positioning device, and a testing lifting device; the self-focusing optical testing device adopts the aforementioned optical testing device for the end face of a deep cavity fiber optic cable, and is used for deep cavity insertion / removal positioning and optical testing of the end face of the deep cavity fiber optic cable; the non-contact cleaning device is used for deep cavity insertion / removal positioning and non-contact fluid cleaning of the end face of the deep cavity fiber optic cable, and the contact cleaning device is used for deep cavity insertion / removal positioning and contact cleaning of the end face of the deep cavity fiber optic cable; the product positioning platform is located in front of the cleaning and testing station and is used for loading and unloading the product to be tested and for product positioning.

[0022] Compared to existing technologies, the advantages of this invention are as follows: The overall application adopts a Sham structure design, enabling clear imaging of the entire effective area of ​​the image; the front end integrates a prism to deflect the optical path, and the object-side off-axis telecentric design eliminates perspective errors; the dual-optical-path design allows for simultaneous detection of two end faces in a single operation, improving detection efficiency; the prism front end results in a shorter working distance, theoretically allowing for a larger field of view and superior resolution; the field of view is unaffected and larger; the illumination optical path is strictly perpendicular to the object plane to achieve bright-field imaging, resulting in more uniform illumination and effectively improving detection accuracy. This application can be widely applied in fields such as optical communication, 3C, and semiconductors, where deep cavity scenarios are present. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the optical module under test; Figure 2 and Figure 3 Schematic diagrams from different perspectives of an embodiment of an optical detection device for the end face of a deep cavity fiber optic cable; Figure 4 This is a schematic diagram of Example 2; Figure 5 This is a schematic diagram of Example 3; Figure 6 Schematic diagram of Example 4; Figure 7 A schematic diagram of Example 5; Figure 8 This is a schematic diagram of the positioning unit; Figure 9 and Figure 10 A schematic diagram of an embodiment with a focusing unit; Figure 11 This is a schematic diagram of the cleaning and testing equipment; Figure 12 This is a schematic diagram of a cleaning and testing station; Figure 13 This is a flowchart of the cleaning detection method. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, 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.

[0025] Example 1 An optical detection device for the end face of a deep cavity fiber, see [reference needed]. Figure 2 and Figure 3 The optical detection device at the end face of the deep cavity fiber includes a teleconverter group 40, an imaging turning unit 30, and multiple imaging units 70 arranged sequentially from front to back.

[0026] The imaging deflection unit 30 is used to deflect the image and expand the space, and the number of extended optical paths matches the number of imaging units 70 behind it; the teleconverter group 40 adopts a telecentric optical path for long-distance image transmission in narrow spaces.

[0027] In the specific example, the number of extended optical paths of the imaging transition unit 30 is designed to be two, and correspondingly, the imaging unit 70 is also designed to be two.

[0028] The imaging deflection unit 30 is located at the rear end of the teleconverter group 40, and the direction of extending the optical path is deflected from the rear end of the teleconverter group 40 to the outer periphery.

[0029] For the number of dual extended optical paths, the deflection direction of the imaging deflection unit 30 is bidirectional, such as up and down, up and left, up and right, down and left, and left and right. In the illustrated example, the deflection direction of the imaging deflection unit 30 is to the left and right.

[0030] The teleconverter assembly 40 employs a multi-segment relay lens assembly to extend the detection optical path. In specific examples, the teleconverter assembly 40 uses a two-segment or three-segment relay lens assembly, taking a three-segment 10X relay system as an example. Of course, four-segment or five-segment assemblies can also be used, as long as they meet the optical and detection distance requirements. This design allows it to be inserted into the deep cavity A of the optical module to achieve vertical or inclined alignment of the fiber end face; this embodiment is particularly suitable for inclined fiber end faces. In specific examples, the length of the teleconverter assembly 40 is 150-200mm, which is sufficient to meet the deep cavity distance requirements of the product under test.

[0031] Multiple imaging units 70, designed based on Scherm's law, are non-connected and positioned behind the imaging deflection unit 30. Each imaging unit 70 can clearly image the entire surface under test at once, solving the shallow depth-of-field problem caused by high resolution. In the illustrated example, the imaging unit 70 is interface-free and non-contactly positioned behind the light path deflected by the imaging deflection unit 30, with the imaging unit 70 arranged at an angle relative to the imaging deflection unit 30. The imaging unit 70 uses a CMOS or CCD camera, and the tilted arrangement ensures that the angle between the camera's imaging sensor surface and the imaging output light path of the imaging tube lens 60 ranges from 60° to 80°.

[0032] Example 2 See Figure 4 Based on Example 1, a detection prism 50 is set at the front end of the teleconverter group 40. After being deflected by the oblique optical path of the detection prism 50, the light is perpendicularly irradiated onto the end face to be measured, thus realizing the object-side off-axis telecentric design.

[0033] In the specific example, the detection prism 50 is a wedge prism, and the angle between the light path and the test surface formed by the wedge prism and the horizontal plane is in the range of 5°-10°.

[0034] Example 3 See Figure 5 Based on Embodiment 1 or Embodiment 2, an imaging tube lens 60 is provided at the rear end of the imaging turning unit 30 in an number equal to that of the imaging unit 70. The imaging tube lens 60 adopts an image-side telecentric design to eliminate image-side perspective error.

[0035] Example 4 See Figure 6 Based on the aforementioned embodiments, the optical detection device for the deep cavity fiber end face is equipped with an illumination optical path. Specifically, the optical detection device for the deep cavity fiber end face also includes an external light source, a light source tube lens 10, and an illumination turning unit 20. The external light source forms coaxial light through the light source tube lens 10, and the illumination turning unit 20 is used to turn the illumination beam into the teleconverter group 40.

[0036] In a specific example, the external light source is a fiber optic point source with adjustable wavelength. The number of deflection optical paths in the illumination deflection unit 20 matches the number of deflection optical paths in the imaging deflection unit 30. The illustrated example shows two paths. Correspondingly, two sets of external light sources and light source tube lenses 10 are set.

[0037] The illumination deflection unit 20 employs a combination of a reflector and a semi-transparent mirror to deflect the illumination source into the teleconverter group 40; the imaging deflection unit 30 employs a double-reflector design to transmit the image and expand the space through double reflection. Specifically, the illumination deflection unit 20, with its combination of a reflector and a semi-transparent mirror, is used to deflect the illumination source into the teleconverter group 40, achieving bright-field illumination.

[0038] Optical path setup: The light source tube lens 10, the illumination deflection unit 20, the teleconverter group 40, and the detection prism 50 constitute the bright field illumination optical path; the detection prism 50, the teleconverter group 40, the imaging deflection unit 30, the imaging tube lens 60, and the imaging unit 70 constitute the imaging optical path.

[0039] The device includes multiple sets of light source tube lenses 10, illumination deflection units 20, imaging deflection units 30, teleconverter lens group 40, detection prism 50, imaging tube lens 60, and imaging unit 70, thereby simultaneously detecting the test surfaces of multiple products under test. The illustrated example uses a two-set design side by side, which can simultaneously detect two fiber optic end face products. Of course, it can also be set up with three sets, depending on the actual scenario.

[0040] Example 5 Based on the above embodiments, see Figure 7 and Figure 8 The teleconverter assembly 40 is also provided with a positioning unit 80 at its front end. The positioning unit 80 includes an overall positioning part 81 and a test surface positioning part 82 provided on the positioning body 83. The test surface positioning part 82 is located in front of the outer periphery of the detection prism 50 to position the test surface. The positioning surface of the overall positioning part 81 is located in front of the positioning surface positioning part 82 to position the entire test product.

[0041] Specifically, the positioning unit 80 is detachably connected to the front end of the teleconverter assembly 40 via a positioning body 83 surrounding the detection prism 50. Furthermore, a positioning guide groove 84 is provided on the positioning body 83 of the positioning unit 80 for positioning guidance of the product under test.

[0042] Example 6 See Figure 9 and Figure 10The optical detection device at the end face of the deep cavity fiber also includes a focusing unit 90. The focusing unit 90 includes a camera mount 91, a focusing slide 92, a focusing driver 93, and a detection housing 94. The camera mount 91 is connected to the imaging unit 70. The fixing part of the focusing slide 92 and the focusing driver 93 are connected to the inner side of the detection housing 94. The focusing driver 93 drives the imaging unit 70 at the camera mount 91 to move to achieve focusing.

[0043] The setting of the focusing unit 90 enables the imaging unit 70 to achieve independent autofocus, which is also an advantage of the interface-free SAM structure design of the imaging unit 70.

[0044] In summary, the core innovations of this application are as follows: ① This invention provides a new illumination approach, using a wedge prism instead of a reflector and employing built-in coaxial illumination. By adding a wedge prism at the front end of the lens, the light path is deflected, achieving bright-field illumination where the illumination path is completely perpendicular to the inclined surface of the fiber end face; ② Due to the use of a wedge prism, the imaging light path of the fiber end face is also deflected, achieving an off-axis telecentric light path. Combined with the absence of a reflector, the working distance is further reduced, the object-side area (NA) is larger, and the overall illumination and imaging quality is higher, without introducing ghosting; ③ To adapt to the tilt angle, the overall system adopts a Sham structure design, enabling clear imaging of the entire end face in one operation, solving the shallow depth-of-field problem caused by high resolution; ④ This invention uses a dual teleconverter group in the deep cavity region, separating the prism outside the cavity to release space and adding a high-magnification detection module. It employs dual-path simultaneous illumination and imaging, allowing simultaneous detection of both end faces, greatly improving detection efficiency. Therefore, for the detection of inclined fiber end faces in deep cavities, this invention has significant innovations in illumination, field of view coverage, imaging quality, and detection efficiency, and can overcome the shortcomings of existing solutions in this regard.

[0045] In addition, see Figure 11 and Figure 12The present invention also provides a cleaning and testing device for the end face of a deep cavity fiber optic cable using the aforementioned optical testing device. The cleaning and testing device includes a cleaning and testing station 1000 and a product positioning platform 2000. The cleaning and testing station 1000 includes a self-focusing optical testing device 100, a non-contact cleaning device 200, a contact cleaning device 300, a testing area positioning device 400, and a testing lifting device 500. The self-focusing optical testing device 100 uses the aforementioned optical testing device for the end face of a deep cavity fiber optic cable for optical testing of the end face of the deep cavity fiber optic cable. Furthermore, the self-focusing optical testing device 100 adds a lateral movement drive unit along the insertion and removal direction on the basis of the aforementioned optical testing device, so that the self-focusing optical testing device 100 can achieve insertion and removal positioning in the deep cavity of the product to be tested. The non-contact cleaning device 200 is used for deep cavity fiber end face insertion and removal positioning and non-contact fluid cleaning, and the contact cleaning device 300 is used for deep cavity fiber end face insertion and removal positioning and contact cleaning; the product positioning platform 2000 is located in front of the cleaning and testing station 1000 and is used for loading and unloading the product to be tested and product positioning.

[0046] The cleaning and testing station 1000 also includes an inner frame 600 and an outer frame 700. The inner frame 600 is installed inside the outer frame 700 by a testing lifting device 500. The self-focusing optical testing device 100, the non-contact cleaning device 200, the contact cleaning device 300, and the testing area positioning device 400 are arranged inside the inner frame 600. The testing lifting device 500 drives the self-focusing optical testing device 100, the non-contact cleaning device 200, and the contact cleaning device 300 to lift and align with the testing end face area of ​​the product to be tested based on the image obtained by the testing area positioning device 400.

[0047] Between the cleaning and testing station 1000 and the product positioning platform 2000, there is also a product positioning vision module 3000. The product positioning vision module 3000 includes a vertical calibration and alignment camera unit and a horizontal calibration and alignment camera unit set on the product positioning frame, which are used to position the product on the tray on the product positioning platform 2000 below.

[0048] A barcode scanning module 4000 is also installed on the side of the product positioning platform 2000 for scanning the products on the pallet.

[0049] See Figure 13 The cleaning and testing method based on the aforementioned cleaning and testing equipment includes the following steps.

[0050] S1. Loading: The product pallet is transported to the product positioning platform 2000 and the pallet is positioned.

[0051] S2. Product positioning: Visual positioning of the product to be tested on the tray.

[0052] S3. Fiber optic end face positioning: The detection area positioning device 400 performs optical acquisition on the product at the cleaning or detection station to determine the visual positioning of the fiber optic end face to be tested inside the deep cavity of the product.

[0053] S4. Detection: The self-focusing optical detection device 100 performs optical image detection on the positioned end face of the optical fiber to be tested.

[0054] S5. Result Judgment: Based on the test results of S4, if the test result is OK, the test of the product is completed and an OK test result is output; if the test result is NG, non-contact cleaning is performed first, then S4 is entered. If the test result after non-contact cleaning is OK, the test of the product is completed and an OK test result is output; if the test result after non-contact cleaning is NG, contact cleaning is performed, non-contact cleaning is entered again, and then S4 is entered again. If the test result is OK, the test of the product is completed and an OK test result is output; if the test result is NG, the test of the product is also completed and an NG test result is output.

[0055] The method employs a three-time consecutive NG (Not From Good) judgment rule, which improves the detection yield and ensures the accuracy of the equipment.

[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An optical detection device for the end face of a deep cavity optical fiber, characterized in that: The optical detection device for the deep cavity fiber end face includes a teleconverter group (40), an imaging turning unit (30), and multiple imaging units (70) arranged sequentially from front to back. The imaging turning unit (30) is used to turn the image transmission and expand the space, and the number of extended optical paths matches the number of imaging units (70) behind it; the teleconverter group (40) adopts a telecentric optical path for long-distance image transmission in narrow spaces.

2. The optical detection device for the deep cavity fiber end face according to claim 1, characterized in that: The imaging deflection unit (30) is located at the rear end of the teleconverter group (40), and the direction of the extended optical path is deflected from the rear end of the teleconverter group (40) to the outer periphery.

3. The optical detection device for the deep cavity fiber end face according to claim 1, characterized in that: The teleconverter group (40) adopts a multi-segment relay group to extend the detection optical path.

4. The optical detection device for the deep cavity fiber end face according to claim 1, characterized in that: Multiple imaging units (70) designed based on Scham's law are disposed non-connected behind the imaging transition unit (30).

5. The optical detection device for the deep cavity fiber end face according to claim 4, characterized in that: The imaging unit (70) is designed without an interface and is non-contactly positioned behind the light path deflected by the imaging turning unit (30). The imaging unit (70) is arranged at an angle relative to the imaging turning unit (30).

6. The optical detection device for the deep cavity fiber end face according to claim 1, characterized in that: A detection prism (50) is set at the front end of the teleconverter assembly (40). After being deflected by the oblique light path of the detection prism (50), the light is vertically irradiated onto the end face to be measured, thus realizing the object-side off-axis telecentric design.

7. The optical detection device for the deep cavity fiber end face according to claim 1, characterized in that: The imaging tube (60) is set at the rear end of the imaging turning unit (30) with the same number of imaging units (70). The imaging tube (60) adopts an image-side telecentric design to eliminate image-side perspective error.

8. The optical detection device for the deep cavity fiber end face according to claim 1, characterized in that: The optical detection device for the deep cavity fiber end face also includes an external light source, a light source tube lens (10) and an illumination turning unit (20). The external light source forms coaxial light through the light source tube lens (10), and the illumination turning unit (20) is used to turn the illumination beam into the teleconverter group (40).

9. The optical detection device for the deep cavity fiber end face according to claim 1, characterized in that: A positioning unit (80) is also provided at the front end of the teleconverter assembly (40). The positioning unit (80) includes an overall positioning part (81) and a test surface positioning part (82) provided on the positioning body (83). The test surface positioning part (82) is located in front of the outer periphery of the detection prism (50) to position the test surface. The positioning surface of the overall positioning part (81) is located in front of the positioning surface positioning part (82) to position the entire test product.

10. The optical detection device for the deep cavity fiber end face according to claim 1, characterized in that: The optical detection device for the deep cavity fiber end face also includes a focusing unit (90), which includes a camera mount (91), a focusing slide (92), a focusing driver (93), and a detection housing (94). The camera mount (91) is connected to the imaging unit (70), the fixing part of the focusing slide (92) and the focusing driver (93) are connected to the inner side of the detection housing (94), and the focusing driver (93) drives the imaging unit (70) at the camera mount (91) to move to achieve focusing.

11. A cleaning and testing device for the end face of a deep cavity optical fiber, characterized in that: The cleaning and testing equipment includes a cleaning and testing station (1000) and a product positioning platform (2000); the cleaning and testing station (1000) includes a self-focusing optical testing device (100), a non-contact cleaning device (200), a contact cleaning device (300), a testing area positioning device (400), and a testing lifting device (500); the self-focusing optical testing device (100) adopts the optical testing device for the deep cavity fiber end face as described in any one of claims 1-10, and is used for optical testing of the deep cavity fiber end face; the non-contact cleaning device (200) is used for deep cavity insertion and removal positioning and non-contact fluid cleaning of the deep cavity fiber end face, and the contact cleaning device (300) is used for deep cavity insertion and removal positioning and contact cleaning of the deep cavity fiber end face; the product positioning platform (2000) is located in front of the cleaning and testing station (1000) and is used for loading and unloading the product to be tested and for product positioning.

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