Method for controlling thickness of optical module lens coupling glue

Abstract

The invention relates to the technical field of optical communication, in particular to an optical module lens coupling glue thickness control method, which comprises the following steps: fixing a substrate, a laser, an optical isolator and an optical fiber adapter, then fixing the position of a lens in the X-axis direction, and adjusting the positions in the Y-axis direction and the Z-axis direction to maximize the optical power; then, the lens moves downwards in the Z-axis direction until the lens makes contact with the substrate, the downward moving distance of the lens is calculated, namely, the thickness B of glue below the lens is calculated, and whether the B value is within the set glue thickness range or not is judged; and if the optical power is within the specified range or deviates from the specified range and does not exceed d, lifting the lens, dispensing the UV glue, moving the lens back, readjusting the positions in the Y-axis direction and the Z-axis direction to enable the optical power to reach the maximum, then fixing the lens or lifting / pressing the lens for a distance d, and curing the UV glue. According to the invention, fine adjustment can be timely carried out on products whose glue thickness deviates from a specified range and does not exceed d, and the reject ratio of products whose glue thickness does not meet a specification range is reduced.

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 of an optical module lens. Background Art

[0002] Figure 1 It is a schematic diagram of the structure of a typical optical transmitter submodule (TOSA), including a laser 4, a lens 1 7 for collimating the light emitted by the laser 4, an optical isolator 5, a lens 2 8 for coupling the collimated light from the lens 1 7 after passing through the optical isolator 5 into the optical fiber adapter 6, the optical fiber adapter 6, a mounting plate 3 for bonding the laser 4, a substrate 2 for fixing components such as the lens and the optical isolator 5, and a device housing 1. Usually, the optical fiber adapter 6 is installed in the round hole on the right side of the device housing 1 and fixed with glue. Since there is a tolerance in the thickness of the substrate 2 and there is also a tolerance in the installation of the optical fiber adapter 6, the position of the lens 2 8 in the height direction will also vary greatly, resulting in the thickness of the glue 9 below the lens 2 8 varying within a large range. If the glue 9 is too thick, the glue 9 will expand and contract due to temperature changes, which will cause the lens 2 8 to be displaced too much, causing the optical power coupled into the optical fiber adapter 6 to drop, thereby affecting the performance of the optical transmitter submodule. If the glue 9 is too thin, due to the presence of solid particles in the glue 9 itself, the lens 2 8 will not be able to be pressed down, resulting in 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 proportion of products whose glue thickness does not meet the specification range.

[0004] To achieve the above purpose, 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 positions of the lens in the Y-axis and Z-axis directions so that the optical power output from the optical fiber adapter reaches the maximum, 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, dot 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 suction 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 suction 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 modes, 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 modes, the following step is further included after step S7: placing the product with coupled lenses 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, thereby 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 is used to ensure that the glue thickness is back within the set range, thereby greatly reducing the defective proportion 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 drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. 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 creative work.

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

[0031] Figure 2 A flow chart of a method for controlling the thickness of coupling glue of 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. optical fiber adapter; 7. lens one; 8. lens two; 9. UV glue. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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 creative work 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 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 a limitation on the present invention.

[0035] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features; 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 positions of the lens in the Y-axis and Z-axis directions so that the optical power output from the optical fiber adapter reaches the maximum, 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, calculating the distance the lens moves downward, which is the thickness B of the glue below the lens, where the thickness B is equal to the vertical distance between position Z1 and position Z2, and determining 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, then 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 contacts the upper surface of the substrate. The distance that the lens moves downward is the thickness of the glue under the lens. It 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 the glue thickness problem 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, and through 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 contacts 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 direction, the reading of the pressure sensor is continuously observed. When the reading of the pressure sensor is greater than or equal to the 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 implementation method, the pressure sensor is installed on the top of the nozzle. When the lens is not in contact with the upper surface of the substrate, the pressure sensor is not subjected to the reaction force from the substrate, and the reading of the pressure sensor is 0g; when the lens is completely in contact with the upper surface of the substrate, the pressure sensor is subjected to the reaction force from the substrate, and the reading of the pressure sensor is greater than or equal to the preset pressure threshold.

[0052] Specifically, the preset pressure threshold is 50 g, that is, when the reading of the pressure sensor begins to be greater than or equal to 50 g, 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 direction in steps of 1-2 μm. In this embodiment, the lens is moved in steps in the Z-axis direction, and the step length of each movement is 1-2 μm. By adopting a small step, the moment when the lens contacts the substrate is captured in time, thereby improving the accuracy of measuring the thickness of the glue 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 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. When light is emitted from the laser and focused by the lens, it will fall exactly on the receiving end face of the optical fiber adapter, which can minimize the loss of optical signals and improve coupling efficiency.

[0058] Optimally, after step S7, the following step is also included: placing the product with coupled lenses in an oven to further bake and cure the UV glue. Further baking and curing ensures that the UV glue is completely 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 2 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 2; 5) fix the distance between lens 2 8 and fiber adapter 6 in the X-axis direction as the focal length of the lens, adjust the position of lens 2 8 in the Y-axis and Z-axis directions to maximize the optical power coming out of the fiber adapter 6; 6) then lift lens 2 8, and apply glue 9 at the position corresponding to lens 2 on substrate 2; 7) lens 2 returns to the position before lens 2 8 is lifted in step 5), and readjust the position of lens 2 8 in the Y-axis and Z-axis directions to maximize the optical power coming out of the fiber adapter 6; 8) UV cure glue; 9 put the product with coupled lens 2 8 in the oven to bake to further cure the glue and complete the coupling of lens 2 8. This product usually sets the thickness of the glue under the lens 2 8 to be within the range of 60±20um, the thickness tolerance of the substrate 2 is usually ±20um, the installation tolerance of the optical fiber adapter 6 is usually around ±30um, and the added limit tolerance of the two is ±50um. Therefore, it is difficult to control the thickness variation of the glue 9 under the 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 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, using a suction nozzle to pick up a lens and move it to the position of lens 2 between the optical isolator and the optical fiber adapter; specifically, a pressure sensor for monitoring the contact pressure between the lens and the substrate is installed on the suction nozzle;

[0066] S5, 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 so that the optical power output from the optical fiber adapter reaches the maximum, and record the position Z1 of the lens in the Z-axis direction at this time; specifically, the distance between the preset position of the lens in the X-axis direction and the optical fiber adapter is the focal length of the lens;

[0067] S6, moving the suction nozzle and the lens downward along the Z-axis direction at a step of 1 μm, while continuously observing the reading of the pressure sensor. When the reading of the pressure sensor is greater than or equal to 50 g, it is determined that the lens has contacted the upper surface of the substrate, and the suction nozzle and the lens are stopped from being moved downward, and the position Z2 of the lens in the Z-axis direction at this time is recorded;

[0068] S7, calculating the distance the lens moves downward, which is the thickness B of the glue below the lens, and determining 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 is marked as defective;

[0073] a) Lift the lens, 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-axis and Z-axis directions to maximize the optical power output from the fiber optic adapter;

[0074] b) Lift the lens, 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-axis and Z-axis directions to maximize the optical power output from the fiber optic adapter, and then move the lens upward by 10μm;

[0075] c) Lift the lens up, 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-axis and Z-axis directions to maximize the optical power output from the fiber optic adapter, and then move the lens down 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 judge the products that do not meet the standards as defective products, thereby reducing the potential risk of product failure; at the same time, for products whose glue thickness deviates from the specification range by no more than 10 μm, the position of the lens is adjusted in time, and the change of the glue thickness of the lens is controlled within the range of ±20 um, 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 principle of the present invention should be included in the protection scope 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 inside 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 a defective product; 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, characterized in that: 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 as claimed in claim 2, characterized in that: 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 as claimed in claim 3, characterized in that: The preset pressure threshold is 50 g.

5. The method for controlling the thickness of the optical module lens coupling glue as claimed in claim 1, characterized in that: 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 as claimed in claim 1, characterized in that: In step S6, the glue thickness range is set according to the optical performance of the product, manufacturing tolerance, 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 as claimed in claim 1, characterized in that: In step S6, d is 10 - 20 μm.

8. The method for controlling the thickness of the optical module lens coupling glue as claimed in claim 1, characterized in that: In step S1, after fixing the substrate, laser, optical isolator, and fiber optic adapter inside 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 as claimed in claim 1, characterized in that: 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, characterized in that: After step S7, the following steps are further included: Put the product with the lens coupled into an oven for further baking to cure the UV glue.

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