A method for controlling the thickness of optical module lens coupling glue

Abstract

The present invention relates to the field of optical communication technology, and more specifically to a method for controlling the thickness of the coupling glue of an optical module lens. The method comprises the following steps: first, fixing a substrate, a laser, an optical isolator, and an optical fiber adapter, then fixing the position of the lens in the X-axis direction, adjusting the positions in the Y-axis and Z-axis directions to maximize the optical power; then, moving the lens downward in the Z-axis direction until it contacts the substrate, calculating the distance the lens moves downward as the thickness B of the glue below the lens, and determining whether the value B is within a set glue thickness range; if it is within a specified range or deviates from the specified range by no more than d, then raising the lens, applying UV glue, moving the lens back, and re-adjusting the positions in the Y-axis and Z-axis directions to maximize the optical power; then, the lens is not moved or raised / pressed a distance d, and then the UV glue is cured. The present invention can promptly fine-tune products whose glue thickness deviates from the specified range by no more than d, thereby reducing the defective ratio of products whose glue thickness does not meet the specification range.

Description

Technical Field

[0001] The present invention relates to the technical field of optical communications, and in particular to a method for controlling the thickness of coupling glue for an optical module lens. Background Art

[0002] Figure 1 This is a schematic diagram of the structure of a typical Transmitter Optical Sub-Module (TOSA). It includes a laser 4, a lens 1 7 that collimates the light emitted by the laser 4, an optical isolator 5, a lens 2 8 that couples the collimated light from lens 1 7 after passing through the optical isolator 5 into a fiber adapter 6, the fiber adapter 6, a mounting plate 3 for bonding the laser 4, a substrate 2 that secures the lens and optical isolator 5, and a device housing 1. Typically, the fiber adapter 6 is mounted in a circular hole on the right side of the device housing 1 and secured with glue. Due to thickness tolerances in the substrate 2 and the mounting of the fiber adapter 6, the height position of lens 2 8 can vary significantly, resulting in a wide range of variations in the thickness of the glue 9 beneath lens 2 8. If the glue 9 is too thick, it expands and contracts with temperature fluctuations, causing lens 2 8 to move significantly, resulting in a drop in the optical power coupled into the fiber adapter 6 and affecting the performance of the transmitter sub-module. If the glue 9 is too thin, solid particles in the glue 9 prevent the lens 2 8 from being pressed down, leading to coupling failure. Summary of the Invention

[0003] The purpose of the present invention is to provide a method for controlling the thickness of the coupling glue of an optical module lens, which can promptly determine products whose glue thickness does not meet the standard as defective products, thereby reducing the potential risk of product failure. At the same time, it can promptly fine-tune products whose glue thickness slightly exceeds the specified range, thereby reducing the defective ratio of products whose glue thickness does not meet the specification range.

[0004] To achieve the above object, the technical solution of the present invention is a method for controlling the thickness of the coupling glue of the optical module lens, comprising the following steps:

[0005] S1. Fix the substrate, laser, optical isolator, and optical fiber adapter in the device housing;

[0006] S2, power on the laser;

[0007] S3, pick up a lens and move it between the optical isolator and the fiber adapter;

[0008] S4. Fix the position of the lens in the X-axis direction at a preset position, adjust the position of the lens in the Y-axis and Z-axis directions to maximize the optical power output from the fiber optic adapter, and record the position Z1 of the lens in the Z-axis direction at this time;

[0009] S5. Move the lens downward along the Z-axis until the lens touches the upper surface of the substrate, and record the position Z2 of the lens in the Z-axis direction at this time;

[0010] S6. Calculate the distance that the lens moves downward, which is the thickness B of the glue under the lens, and determine whether the value of B is within the set glue thickness range (m, n);

[0011] If B ∈ (m, n), then directly execute step S8 after step S7 is completed;

[0012] If m - d ≤ B ≤ m, where d is a fixed value, then move the lens upward by a distance d after step S7 is completed and then execute step S8;

[0013] If n ≤ B ≤ n + d, then move the lens downward by a distance d after step S7 is completed and then execute step S8;

[0014] If B < m - d or B > n + d, then mark the product as a defective product;

[0015] S7. Lift the lens, apply UV glue at the position corresponding to the lens on the substrate, then move the lens back to position Z1, and readjust the positions of the lens in the Y-axis and Z-axis directions to make the optical power output from the fiber optic adapter reach the maximum;

[0016] S8. Cure the UV glue.

[0017] As one of the implementation manners, in step S3, a nozzle is used to suck the lens, and a pressure sensor for monitoring the contact pressure between the lens and the substrate is installed on the nozzle.

[0018] As one of the implementation manners, in step S5, during the process of moving the lens downward along the Z-axis, continuously observe the reading of the pressure sensor. When the reading of the pressure sensor is greater than or equal to the preset pressure threshold, it is determined that the lens touches the upper surface of the substrate.

[0019] As one of the implementation manners, the preset pressure threshold is 50 g.

[0020] As one of the implementation manners, in step S5, the lens is moved downward along the Z-axis in steps of 1 - 2 μm.

[0021] As one of the implementation manners, in step S6, the glue thickness range is set according to the optical performance of the product, the manufacturing tolerance, and the size of the solid filling particles of the UV glue itself used.

[0022] As one of the implementation manners, in step S6, d is 10 - 20 μm.

[0023] As one of the implementation methods, in step S1, after the substrate, the laser, the optical isolator, and the optical fiber adapter are fixed in the device housing, the electrical connection of the laser is completed by gold wire bonding.

[0024] As one of the implementation modes, in step S4, the distance between the preset position of the lens in the X-axis direction and the optical fiber end face of the optical fiber adapter is the focal length of the lens.

[0025] As one of the implementation methods, step S7 may further include the following step: placing the product with the coupled lens in an oven to further bake and cure the UV glue.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] (1) The present invention can accurately obtain the thickness of the glue under the lens of each product during the coupling process. When the glue thickness does not meet the requirements, the substandard products can be marked as defective products in a timely manner, reducing the risk of product failure caused by glue thickness problems and ensuring the stability and reliability of the product.

[0028] (2) When the glue thickness measured during the coupling process of the present invention deviates from the specified range but does not exceed a certain threshold value d, the lens is lifted up or pressed down a distance d before UV curing. This fine-tuning ensures that the glue thickness is back within the set range, greatly reducing the defective ratio of products whose glue thickness does not meet the specification range. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0030] Figure 1 Schematic diagram of the structure of a typical transmit optical submodule (TOSA);

[0031] Figure 2 Flowchart of a method for controlling the thickness of coupling glue for an optical module lens provided by an embodiment of the present invention;

[0032] In the figure: 1. Device housing; 2. Substrate; 3. Mounting plate; 4. Laser; 5. Optical isolator; 6. Fiber optic adapter; 7. Lens 1; 8. Lens 2; 9. UV glue. DETAILED DESCRIPTION

[0033] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0034] In the description of the present invention, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0035] The terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, features specified as "first" or "second" may explicitly or implicitly include one or more of such features; and in the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0036] like Figure 2 As shown, this embodiment provides a method for controlling the thickness of coupling glue of an optical module lens, comprising the following steps:

[0037] S1. Fix the substrate, laser, optical isolator, and optical fiber adapter in the device housing;

[0038] S2, power on the laser;

[0039] S3, pick up a lens and move it between the optical isolator and the fiber adapter;

[0040] S4. Fix the position of the lens in the X-axis direction at a preset position, adjust the position of the lens in the Y-axis and Z-axis directions to maximize the optical power output from the fiber optic adapter, and record the position Z1 of the lens in the Z-axis direction at this time;

[0041] S5, moving the lens downward along the Z-axis direction until the lens contacts the upper surface of the substrate, and recording the position Z2 of the lens in the Z-axis direction at this time;

[0042] S6. Calculate the distance the lens moves downward, which is the thickness B of the glue below the lens. Thickness B is equal to the vertical distance between position Z1 and position Z2. Determine whether the value of B is within the set glue thickness range (m, n) below the lens.

[0043] If B ∈ (m, n), then step S8 is directly executed after step S7 is completed;

[0044] If m - d ≤ B ≤ m, where d is a fixed value, then after step S7 is completed, the lens is moved upward by a distance d and then step S8 is executed;

[0045] If n ≤ B ≤ n + d, then after step S7 is completed, the lens is moved downward by a distance d and then step S8 is executed;

[0046] If B < m - d or B > n + d, the product is marked as defective;

[0047] S7. Lift the lens, apply UV glue at the position corresponding to the lens on the substrate, then move the lens back to position Z1, and readjust the positions of the lens in the Y-axis and Z-axis directions to maximize the optical power output from the fiber optic adapter;

[0048] S8. Cure the UV glue.

[0049] In this embodiment, the substrate, laser, optical isolator, and fiber optic adapter are first passively fixed, then the position of the lens in the X-axis direction is fixed, and in an active environment, the positions of the lens in the Y-axis and Z-axis directions are adjusted until the optical power output from the fiber optic adapter reaches the maximum. Then, the lens is moved downward along the Z-axis direction until the lens touches the upper surface of the substrate. The distance by which the lens is moved downward is the thickness of the glue under the lens. This can accurately obtain the thickness of the glue under the lens for each product during the coupling process. When the thickness of the glue deviates from the specified range and exceeds a certain threshold d, the non-compliant products can be promptly marked as defective, reducing the risk of product failure caused by glue thickness problems and ensuring the stability and reliability of the product. When the glue thickness deviates from the specified range but does not exceed a certain threshold d, the lens can be lifted or pressed down by a distance d before the UV glue is cured. By this fine adjustment, the thickness of the glue under the lens can be ensured to be within the set range again, greatly reducing the defective rate of products with glue thickness not meeting the specification range.

[0050] In some embodiments, in step S3, a suction nozzle is used to pick up the lens, and a pressure sensor for monitoring the contact pressure between the lens and the substrate is installed on the suction nozzle. The pressure sensor can be a high-precision and high-sensitivity pressure sensor, which can real-time feedback the contact pressure between the lens and the substrate, providing a basis for accurately judging whether the lens touches the upper surface of the substrate.

[0051] To refine the above embodiment, in step S5, while the lens is moving downward along the Z-axis, the reading of the pressure sensor is continuously observed. When the reading of the pressure sensor is greater than or equal to a preset pressure threshold, it is determined that the lens has contacted the upper surface of the substrate. Since the pressure sensor will sense pressure when the lens contacts the substrate, it is possible to determine whether the lens has contacted the upper surface of the substrate by the reading of the pressure sensor. As an embodiment, the pressure sensor is installed on the top of the suction nozzle. When the lens is not in contact with the upper surface of the substrate, the pressure sensor is not subjected to a reaction force from the substrate, and the pressure sensor reading is 0g; when the lens is completely in contact with the upper surface of the substrate, the pressure sensor is subjected to a reaction force from the substrate, and the pressure sensor reading is greater than or equal to the preset pressure threshold.

[0052] Specifically, the preset pressure threshold is 50g, that is, when the reading of the pressure sensor starts to be greater than or equal to 50g, it is considered that the lens is completely in contact with the upper surface of the substrate.

[0053] Furthermore, in step S5, the lens is moved downward along the Z-axis in steps of 1-2 μm. In this embodiment, the lens is moved in steps along the Z-axis, and the step length of each movement is 1-2 μm. By using small steps, the moment when the lens contacts the substrate is captured in time, thereby improving the accuracy of the glue thickness measurement under the lens during the coupling process.

[0054] In step S6 of this embodiment, the thickness range of the glue below the lens is set according to the optical performance of the product, the manufacturing tolerance, and the size of the solid filling particles of the UV glue itself.

[0055] As one of the implementation modes, in step S6, d is 10-20 μm.

[0056] Furthermore, in step S1, after the substrate, the laser, the optical isolator, and the optical fiber adapter are fixed in the device housing, the electrical connection of the laser is completed by gold wire bonding.

[0057] Optimally, in step S4, the distance between the lens's preset position in the X-axis direction and the fiber end face of the fiber adapter is the focal length of the lens. When light is emitted from the laser and focused by the lens, it lands squarely on the receiving end face of the fiber adapter, minimizing optical signal loss and improving coupling efficiency.

[0058] Optimally, after step S7, the following step is further included: placing the lens-coupled product in an oven to further bake and cure the UV glue. Further baking and curing ensures that the UV glue is fully cured, thereby enhancing the bonding strength and stability between the lens and the substrate and improving the reliability of the product.

[0059] The above control method is described below through a specific embodiment.

[0060] The structure of the optical module is as follows Figure 1 As shown, under normal circumstances, the coupling steps of lens two are as follows: 1) fix the components such as substrate 2, laser 4, fiber adapter 6 and optical isolator 5 inside the device housing 1; 2) complete the electrical connection of laser 4 through gold wire bonding; 3) power on laser 4 to make laser 4 emit light; 4) use a suction nozzle to pick up a lens and move it to the coupling position of lens two; 5) fix the distance between lens two 8 and fiber adapter 6 in the X-axis direction as the focal length of the lens, adjust the position of lens two 8 in the Y-axis and Z-axis directions to maximize the light power coming out of fiber adapter 6; 6) then lift lens two 8, and apply glue 9 at the position corresponding to lens two on substrate 2; 7) lens two returns to the position before lens two 8 is lifted in step 5), and readjust the position of lens two 8 in the Y-axis and Z-axis directions to maximize the light power coming out of fiber adapter 6; 8) UV cure glue; 9 put the product with coupled lens two 8 into the oven for baking to further cure the glue and complete the coupling of lens two 8. This product usually sets the thickness of the glue under lens 2 8 to be within the range of 60±20um. The thickness tolerance of substrate 2 is usually ±20um, and the installation tolerance of optical fiber adapter 6 is usually around ±30um. The added limit tolerance of the two is ±50um. Therefore, it is difficult to control the thickness variation of glue 9 under lens 2 8 within the range of ±20um.

[0061] The method for controlling the thickness of the coupling glue of the optical module lens of the present invention is used to control the thickness of the coupling glue of the second lens, comprising the following steps:

[0062] S1. Fix the substrate, laser, optical isolator, and optical fiber adapter in the device housing;

[0063] S2. Connect the laser to the wire bonding pad on the substrate through gold wire bonding to complete the electrical connection of the laser;

[0064] S3, power on the laser to make it emit light;

[0065] S4. Pick up a lens with a suction nozzle and move it to the position of lens 2 between the optical isolator and the optical fiber adapter; specifically, the suction nozzle is equipped with a pressure sensor for monitoring the contact pressure between the lens and the substrate;

[0066] S5. Fix the position of the lens in the X-axis direction at a preset position, adjust the position of the lens in the Y-axis and Z-axis directions to maximize the optical power output from the fiber optic adapter, and record the Z-axis position Z1 of the lens at this time. Specifically, the distance between the preset position of the lens in the X-axis direction and the fiber optic adapter is the focal length of the lens.

[0067] S6. Move the suction nozzle and lens downward along the Z-axis in 1 μm increments while continuously observing the pressure sensor reading. When the pressure sensor reading is greater than or equal to 50 g, it is determined that the lens has contacted the upper surface of the substrate. Stop moving the suction nozzle and lens downward, and record the Z-axis position Z2 of the lens at this time.

[0068] S7. Calculate the distance the lens moves downward, which is the thickness B of the glue below the lens, and determine whether the value B is within the set glue thickness range (40 μm, 80 μm) below the lens.

[0069] If B∈(40μm, 80μm), then execute step a);

[0070] If 30 μm ≤ B ≤ 40 μm, proceed to step b);

[0071] If 80 μm ≤ B ≤ 90 μm, perform step c);

[0072] If B<30μm or B>90μm, the product will be marked as defective;

[0073] a) Lift the lens and apply UV glue on the corresponding lens position on the substrate. Then move the lens back to position Z1 and readjust the position of the lens in the Y and Z axes to maximize the optical power output from the fiber optic adapter.

[0074] b) Lift the lens and apply UV glue to the corresponding lens position on the substrate. Then move the lens back to position Z1 and readjust the position of the lens in the Y and Z axes to maximize the optical power output from the fiber optic adapter. Then move the lens upward by 10 μm.

[0075] c) Lift the lens and apply UV glue to the corresponding lens position on the substrate. Then move the lens back to position Z1 and readjust the position of the lens in the Y and Z axes to maximize the optical power output from the fiber optic adapter. Then move the lens downward 10μm.

[0076] S8. Curing the UV glue.

[0077] S9. Place the lens-coupled product in an oven to further bake and cure the UV glue to complete the lens coupling.

[0078] The control method of the present invention can accurately know the thickness of the glue under the lens of each product, and can promptly determine the products that do not meet the standards as defective products, thereby reducing the potential risk of product failure; at the same time, the products whose glue thickness deviates from the specification range by no more than 10 μm can be controlled by timely adjusting the position of the lens, so that the change in the glue thickness of the lens is controlled within the range of ±20 μm, thereby reducing the defective proportion of products whose glue thickness does not meet the specification range.

[0079] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for controlling the thickness of coupling glue of an optical module lens, characterized in that: It includes the following steps: S1. Fix the substrate, laser, optical isolator, and fiber optic adapter in the device housing; S2. Power on the laser; S3. Pick up a lens and move it between the optical isolator and the fiber optic adapter; S4. Fix the position of the lens in the X-axis direction at a preset position, adjust the positions of the lens in the Y-axis and Z-axis directions to make the optical power output from the fiber optic adapter reach the maximum, and record the position Z1 of the lens in the Z-axis direction at this time; S5. Move the lens downward along the Z-axis direction until the lens touches the upper surface of the substrate, and record the position Z2 of the lens in the Z-axis direction at this time; S6. Calculate the distance that the lens moves downward, which is the thickness B of the glue under the lens, and determine whether the value of B is within the set glue thickness range (m, n); If B ∈ (m, n), then directly execute step S8 after completing step S7; If m - d ≤ B ≤ m, where d is a fixed value, then move the lens upward by a distance d after completing step S7 and then execute step S8; If n ≤ B ≤ n + d, then move the lens downward by a distance d after completing step S7 and then execute step S8; If B < m - d or B > n + d, then mark the product as defective; S7. Lift up the lens, apply UV glue at the position corresponding to the lens on the substrate, then move the lens back to the position Z1, and readjust the positions of the lens in the Y-axis and Z-axis directions to make the optical power output from the fiber optic adapter reach the maximum; S8. Cure the UV glue.

2. The method for controlling the thickness of the optical module lens coupling glue according to claim 1, wherein: In step S3, a suction nozzle is used to pick up the lens, and a pressure sensor for monitoring the contact pressure between the lens and the substrate is installed on the suction nozzle.

3. The method for controlling the thickness of the optical module lens coupling glue according to claim 2, wherein: In step S5, during the process of moving the lens downward along the Z-axis direction, continuously observe the reading of the pressure sensor. When the reading of the pressure sensor is greater than or equal to the preset pressure threshold, it is determined that the lens touches the upper surface of the substrate.

4. The method for controlling the thickness of the optical module lens coupling glue according to claim 3, wherein: The preset pressure threshold is 50 g.

5. The method for controlling the thickness of the optical module lens coupling glue according to claim 1, wherein: In step S5, the lens is moved downward along the Z-axis direction in steps of 1 - 2 μm.

6. The method for controlling the thickness of the optical module lens coupling glue according to claim 1, wherein: In step S6, the glue thickness range is set according to the optical performance of the product, manufacturing tolerances, and the size of the solid filling particles of the UV glue itself used.

7. The method for controlling the thickness of the optical module lens coupling glue according to claim 1, wherein: In step S6, d is 10 - 20 μm.

8. The method for controlling the thickness of the optical module lens coupling glue according to claim 1, wherein: In step S1, after fixing the substrate, laser, optical isolator, and fiber optic adapter in the device housing, the electrical connection of the laser is completed through gold wire bonding.

9. The method for controlling the thickness of the optical module lens coupling glue according to claim 1, wherein: In step S4, the distance between the preset position of the lens in the X-axis direction and the fiber end face of the fiber optic adapter is the focal length of the lens.

10. The method for controlling the thickness of the optical module lens coupling glue according to claim 1, wherein: After step S7, it further includes the following step: Place the product with the coupled lens in an oven for further baking to cure the UV glue.

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